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The Consistency of Inconsistency in Serial Homicide: Patterns of Behavioural Change across Series
Abstract
Linkage analysis is a crucial part of the investigative process when faced with a possible series of related offences. Establishing behavioural consistency (i.e., offender's behaviours consistently present across the series) is at the core of linkage. Recent empirical studies have found little evidence of consistency looking at either individual or groups of behaviours in serial homicide. It is argued that behavioural changes are rooted in the changing cognitive strategies that offenders use to reach their ultimate goal (i.e. the commission of multiple homicides). Factors that could account for these changes include learning, situational factors, loss of control, and changes in the offender's fantasy. Patterns of behavioural change have been identified in serial crimes, such as rape. However, no empirical studies have looked at patterns of behavioural change in serial homicide. The present study examined patterns of consistency and change using a combination of thematic and behavioural subgroup approaches that use Multidimensional Scaling. Thematic differentiation indicative of behavioural manifestations of cognitive strategies was found in all three examined subgroups: planning, wounding, and offender–victim interaction, and patterns of change within these subgroups provided support for the above theories. Looking at behavioural patterns rather than individual behaviours, may be a more fruitful way of examining consistency in serial homicide, and could have significant implications for linkage analysis. Copyright © 2010 John Wiley & Sons, Ltd.
... Salfati (2019) explains that offenders' behavioral inconsistency poses a challenge for linkage in that throughout an offender's criminal career, he or she may be inconsistent in their actions as they progress through their series. Rather than looking at behavioral inconsistencies as deviations, Sorochinski and Salfati (2010) stressed the importance of identifying such inconsistencies as patterns of behavioral change. Such behavioral changes are usually due to the offender experimenting in efforts to find the best strategy to commit and complete the offense but what appears to stay consistent is the way the offender interacts with the victim. ...
... One model that has been commonly used to behaviorally classify violent crime scenes as well as to determine the behavioral consistency across multiple crimes within series has been the Interpersonal Model (Canter, 2000). This model has been widely tested on different samples of violent crime, including sexual assault (Canter and Ioannou, 2004;Canter and Youngs, 2009), attempted homicide (Fritzon and Ridgway, 2001) and serial homicide Salfati et al., 2014;Sorochinski and Salfati, 2010). Canter (2000) asserted that the role an offender attributes to the victim affects how they engage with the victim. ...
... Canter (2000) suggested three potential victim roles: 1) victim as person-where the victim has some sort of personal significance to the offender-2) victim as vehicle-where the offender uses the victim to get what he or she wants (such as sex or money) and 3) victim as object-where the offender treats the victim as though he or she is an inanimate object, doing things to the victim rather than with the victim. Notably, previous research (e. g., Salfati et al., 2014;Sorochinski and Salfati, 2010) consistently finds that in serial crime, the 'victim as person' classification is not apparent, and commonly, only two types are identified. That is so because in serial crime, the victim is rarely of personal significance to the offender. ...
Wrongful conviction of an innocent person is an extreme type of injustice that plagues the criminal justice system today. Wrongful conviction for a sexual offense is especially traumatic for the individual due to the inherent stigma surrounding this type of crime; however, there is a dearth of research focusing on the unique aspects of both the offense and the investigation that may contribute to those convictions. The current study sought to answer the following research questions: 1-Are most sexual assault wrongful convictions in series inter-racial? 2-Does relational misattribution play a role in wrongful conviction for sexual assault? 3-Where in the series do wrongful convictions occur? 4-Do wrongful convictions in serial sexual assault cases occur primarily due to behavioral inconsistency on the part of the perpetrator (i.e., the crime for which there is a wrongful conviction appears to be significantly different from the rest of the series) leading to linkage blindness? 5-To what extent does police misconduct and other investigative issues play a role in mishandling of the offense as a one-off as opposed to part of series? Data for this study included 43 violent sexual series where a proven wrongful conviction was present for at least one of the crimes. Results suggest that thorough investigation, evidence testing, and the ability to reopen cases after similar incidents can reduce wrongful sexual assault convictions. Distinguishing between group and solo offending, stranger and acquaintance offenses, and developing investigative models that account for serial crime behavior change can improve investigative accuracy.
... Behaviours that often coexist will be arranged close to each other, while those that do not occur together will be placed far apart. In order to carry out the whole procedure, one should first remove variables that occur in more than 50% of cases, or in less than 2% (Sorochinski, Salfati, 2010). Too frequent data are not taken into account as they disturb the results. ...
... Gierowski, Jaśkiewicz-Obydzińska, 2002). Współczynnik Jaccarda traktowany jest jako narzędzie relatywnie odporne na braki danych, natomiast skalowanie wielowymiarowe pozwala operować na wyjątkowo rzadkich danych (Sorochinski, Salfati, 2010). MDS polega na ograniczeniu wymiarów na podstawie odległości między punktami i obrazowaniu na płaszczyźnie (lub dowolnej n-wymiarowej przestrze-ni) punktów odpowiadających opisywanym zachowaniom. ...
... Zachowania, które często współwystępują, będą ułożone blisko siebie, natomiast te, które nie występują razem -daleko. Aby przeprowadzić całą procedurę, należy najpierw usunąć zmienne, które występują w ponad 50% przypadków lub w poniżej 2% (Sorochinski, Salfati, 2010). Zbyt częste dane nie są brane pod uwagę, gdyż zaburzają wyniki. ...
The aim of the article was to study the distribution of distances travelled for a sample of the Polish population of perpetrators. The analysis covered burglaries and robberies in Warsaw. The results point to the key role of the analysis of the behaviour at the crime scene and its characteristics in the estimation of the journey to crime distance, which is partly consistent with the hypotheses put forward. The results show that perpetrators are ready to travel longer distances if the event is associated with a greater profit or increased risk. However, differences in the distribution of the distances travelled are not as significant as suggested by previous research. The reasons for this and potential consequences are discussed in this paper.
... Other studies done in the area of linking serial sexual assaults using random pairings have since then highlighted control as a key variable Woodhams & Labuschagne, 2012). Sorochinski and Salfati (2010) in a study on consistency behavioral patterns in serial homicide confirmed this finding by showing that individual crime scenes could be distinguished in terms of the control element behind planning behaviors, type of violence, and the interaction with the victim. Sorochinski and Salfati (2018) in a recent study on behavioral consistency patterns in serial sexual assault additionally confirmed that control and violent behavior subtypes were the most useful for classification, but additionally found that they could best be understood quantitatively (i.e., in terms of the degree of the behavior employed). ...
... Salfati and Bateman (2005), the first study in the field to empirically investigate behavioral consistency patterns across series, reported that 70% of series in their study included hybrids and so were excluded from the consistency analysis. Sorochinski and Salfati (2010) in their study included hybrids, but only provided case study-level analysis. However, their study provided a clear insight into the complexities of trying to understand consistency when these are included in any consistency analysis. ...
... An additional emerging result in the consistency literature is that although offenders may outwardly appear inconsistent, there may still be consistent patterns to their inconsistency (Salfati, 2008). Sorochinski and Salfati (2010) in a study on serial homicide showed that although individual crime scenes could be distinguished in terms of planning, type of violence, and the interaction with the victim, offenders did not display a linear consistency in all of these as the series progressed. However, distinct trajectories of change, such as escalation or de-escalation, situation-induced learning, and evolvement of sexual fantasy could be identified in most series, effectively reducing the proportion of series that would have previously been deemed as inconsistent. ...
Sex workers as a group are one of the more common targets in serial homicide, yet the most likely to go unsolved. Part of the reason for this is the difficulty in linking individual crime scenes to a series, especially in those series where offenders not only target sex worker victims but also target non-sex worker victims. Inconsistencies in both victim targeting and behaviors engaged in across series add to the difficulties of linking and solvability in these types of crimes. The current study aimed to add to the current body of literature on serial crime linkage by examining not only the most salient behavioral indicators useful for crime scene classification of serial homicides that involve sex worker victims but also examine the trajectories of behavioral change that can help link apparently inconsistent crime scenes and proposes the new Model for the Analysis of Trajectories and Consistency in Homicide (MATCH). The study examines 83 homicide series, including 44 (53%) series where all victims were sex workers and 39 (47%) series that included a mix of sex workers and non-sex worker victims. Using the MATCH system allowed for the majority of series to be classified to a dominant trajectory pattern, over half as many as a traditional consistency analysis that focusses on behavioral similarity matching. Results further showed that Sex Worker Victim series were almost three times more consistent across their series than Mixed-Victim series, not only in victim selection but also in the overall behavioral patterns. Findings are discussed in line with theoretical and psychological issues relating to understanding the nature of behavioral consistency and the importance of going beyond simple matching toward a model that allows for the identification of consistency in seemingly inconsistent series, as well as investigative implications relating to linking serial crimes.
... In much of the literature on behavioral crime scene analysis and behavioral consistency, even when it focuses on behavior, the underlying psychological focus has been on how these behaviors may reflect something about how the offender interacts with the victim. At the heart of the behavioral crime scene analysis work, therefore, has been the question of the role of the victim (Canter, 1994;Salfati, Horning, Sorochinski, & Labuschagne, 2015;Salfati, James, & Ferguson, 2008;Sorochinski & Salfati, 2010). Proulx (2007), in his comprehensive report on the current understanding of sexual homicide, also highlights the importance of not only focusing on what offenders do during their crimes but also on how these offenders differ depending on the victim group they target. ...
... The location, where the crime occurs and where the body of a victim is found, has been one of the key differentiating and useful factors identified in studies focusing on linking and crime classification as part of the set of planning behaviors offenders engage in (e.g., Beauregard & Field, 2008;Sorochinski & Salfati, 2010). Salfati (2007Salfati ( , 2013, in a U.S. sample, estimated that 43% of sex workers and 44% of non-sex workers were sexually assaulted. ...
... Furthermore, wounding and weapon selection have also been highlighted as key differentiating factors in sexual versus nonsexual homicides (e.g., Beauregard & Martineau, 2014;Beauregard & Proulx, 2002;Chan & Heide, 2008), as well as in studies looking at behavioral consistency and linkage in homicides (e.g., Bateman & Salfati, 2007;Hickey, 2016;Sorochinski & Salfati, 2010). Although comparisons of weapon choice in sexual versus nonsexual homicides find that strangulation is the method of choice in sexually motivated crimes, studies focusing on homicide series also highlight that the type of weapon and the degree/severity of wounding may vary across series. ...
Contrary to popular misconceptions, offenders who kill sex workers as part of their series exhibit substantial variability in their victim selection and behavioral patterns, thus creating additional issues for the investigation of these crimes. This article first aims to outline differences in the demographics of crime scene actions present in homicide series with exclusively sex worker victims and series that includes both sex worker and non–sex worker victims, with the aim of understanding the crime scene aetiology of these two different types of series. Second, the research aims to determine between-series differences of victimology as well as crime scene action between sex worker series and mixed-victim series. Third, the research focuses on mixed-victim series and aims to determine the within-series similarities of victimology and crime scene actions, that is, what factors link sex worker victims and non–sex worker victims in the same series. Data were collected through a large-scale review of international media sources to identify solved serial homicide cases that have included at least one sex worker. Of the 83 series looked at, 44 (53%) included sex worker victims only, and 39 (47%) of the series included both sex worker and non–sex worker victims. The findings highlight the challenges that these types of crime present for investigation and the implications they have on current crime analysis research and practice, and results are discussed in line with theoretical and psychological issues relating to understanding differentiation and similarity, as well as investigative implications relating to linkage blindness and linking of serial crimes.
... Most of these studies have specifically focused on resolving the methodological dilemma of how to best use crime scene behaviors to link serial offenses. However, of these 40 studies, only six specifically focused on serial homicide (Bateman & Salfati, 2007;Salfati & Bateman, 2005;Salfati, Horning, Sorochinski, & Labuschagne, 2015;Salo, et al., 2012;Santtila et al., 2008;Sorochinski & Salfati, 2010), and 13 involved series of sexual offenses (Bennell, Jones, & Melnyk, 2009;Grubin et al., 2001;Harbers, Deslauriers-Varin, Beauregard, & van der Kemp, 2012;Hewitt & Beauregard, 2014;Leclerc, Lussier, & Deslauriers-Varin, 2015;Kearns, Salfati, & Jarvis, 2011;Slater, Woodhams, & Hamilton-Giachritsis, 2015;Winter et al., 2013;Woodhams, Hollin, & Bull, 2008;Woodhams & Labuschagne, 2011). Sorochinski and Salfati's (2018) review of these linking studies (2018) show that over half of the studies examined the possibilities of behavioral linking using only two crimes from a series, either two consecutive crimes (e.g. ...
... However, the consistency discussed is far from what is necessary for behavioral linking to be considered empirically validated and useful in practice, which would only be useful if studies could show that offenders are indeed consistent in all, or the vast majority of their crimes, as shown by either individual behaviors they engage in or subtypes. With early studies showing that offenders don't show the consistency patterns hypothesized to exist, where their crimes are similar across their series, recent studies (e.g., Hewitt & Beauregard, 2014;Leclerc et al., 2015;Salfati, 2009;Sorochinski & Salfati, 2010) have suggested that consistency needs to be looked at in a much broader way, and highlight the importance of looking beyond stability of behavior and of additionally incorporating an understanding of consistency in terms of patterns of behavioral change. Salfati (2009) suggests that these patterns may be usefully seen not as consistency in certain behaviors or patterns of behaviors, but instead as the patterns of change, as the offender moved from one crime to the next. ...
... Of the 6 serial homicide and 13 sexual offense studies on linking mentioned above, only 4 of the studies on serial homicide (Bateman & Salfati, 2007;Salfati & Bateman, 2005;Sorochinski & Salfati, 2010) and 2 of the studies on sexual assault (Kearns et al., 2011;Sorochinski & Salfati, 2017) specifically looked at the issue of behavioral consistency. ...
... In much of the literature on behavioral crime scene analysis and behavioral consistency, even when it focuses on behavior, the underlying psychological focus has been on how these behaviors may reflect something about how the offender interacts with the victim. At the heart of the behavioral crime scene analysis work, therefore, has been the question of the role of the victim (Canter, 1994;Salfati, Horning, Sorochinski, & Labuschagne, 2015;Salfati, James, & Ferguson, 2008;Sorochinski & Salfati, 2010). Proulx (2007), in his comprehensive report on the current understanding of sexual homicide, also highlights the importance of not only focusing on what offenders do during their crimes but also on how these offenders differ depending on the victim group they target. ...
... The location, where the crime occurs and where the body of a victim is found, has been one of the key differentiating and useful factors identified in studies focusing on linking and crime classification as part of the set of planning behaviors offenders engage in (e.g., Beauregard & Field, 2008;Sorochinski & Salfati, 2010). Salfati (2007Salfati ( , 2013, in a U.S. sample, estimated that 43% of sex workers and 44% of non-sex workers were sexually assaulted. ...
... Furthermore, wounding and weapon selection have also been highlighted as key differentiating factors in sexual versus nonsexual homicides (e.g., Beauregard & Martineau, 2014;Beauregard & Proulx, 2002;Chan & Heide, 2008), as well as in studies looking at behavioral consistency and linkage in homicides (e.g., Bateman & Salfati, 2007;Hickey, 2016;Sorochinski & Salfati, 2010). Although comparisons of weapon choice in sexual versus nonsexual homicides find that strangulation is the method of choice in sexually motivated crimes, studies focusing on homicide series also highlight that the type of weapon and the degree/severity of wounding may vary across series. ...
For details of this work please see: https://www.researchgate.net/publication/331501355_Sex_Worker_Homicide_Series_Profiling_The_Crime_Scene
... Other studies done in the area of linking serial sexual assaults using random pairings have since then highlighted control as a key variable Woodhams & Labuschagne, 2012). Sorochinski and Salfati (2010) in a study on consistency behavioral patterns in serial homicide confirmed this finding by showing that individual crime scenes could be distinguished in terms of the control element behind planning behaviors, type of violence, and the interaction with the victim. Sorochinski and Salfati (2018) in a recent study on behavioral consistency patterns in serial sexual assault additionally confirmed that control and violent behavior subtypes were the most useful for classification, but additionally found that they could best be understood quantitatively (i.e., in terms of the degree of the behavior employed). ...
... Salfati and Bateman (2005), the first study in the field to empirically investigate behavioral consistency patterns across series, reported that 70% of series in their study included hybrids and so were excluded from the consistency analysis. Sorochinski and Salfati (2010) in their study included hybrids, but only provided case study-level analysis. However, their study provided a clear insight into the complexities of trying to understand consistency when these are included in any consistency analysis. ...
... An additional emerging result in the consistency literature is that although offenders may outwardly appear inconsistent, there may still be consistent patterns to their inconsistency (Salfati, 2008). Sorochinski and Salfati (2010) in a study on serial homicide showed that although individual crime scenes could be distinguished in terms of planning, type of violence, and the interaction with the victim, offenders did not display a linear consistency in all of these as the series progressed. However, distinct trajectories of change, such as escalation or de-escalation, situation-induced learning, and evolvement of sexual fantasy could be identified in most series, effectively reducing the proportion of series that would have previously been deemed as inconsistent. ...
For details of this work please see: https://www.researchgate.net/publication/331501443_MATCH_A_New_Approach_for_Differentiating_Linking_Series_of_Sex_Worker_Homicides_and_Sexual_Assaults
... Landau (as cited in Smith, 2000) stressed that cross-cultural research is needed, not only to increase our knowledge on homicide from different countries but also to test Western-based theories in other cultural contexts. The expressive/instrumental dichotomy was recently reproduced in studies from different countries such as the United States (Salfati & Bateman, 2005;Sorochinski & Salfati, 2010), Belgium (Thijssen & de Ruiter, 2011), Greece (Salfati & Haratsis, 2001), Canada (Salfati & Dupont, 2006), Finland (Santtila et al., 2001) and Japan (Zaitsu, 2010). Although these studies showed that a single framework can be applicable to homicides from different countries, they also highlighted the importance of the awareness of national differences and the need to further explore how these differences may be manifested in the behaviors offenders engage in at the crime scene. ...
... Although these studies showed that a single framework can be applicable to homicides from different countries, they also highlighted the importance of the awareness of national differences and the need to further explore how these differences may be manifested in the behaviors offenders engage in at the crime scene. For example, Sorochinski, Salfati, and Labuschagne (2015; see also Sorochinski & Salfati, 2010) explored two domains for local contextual differences: (a) tool availability and physical environment, as well as (b) psychological factors. Interestingly, a certain weapon (e.g., an illegal firearm) may be more accessible in the United States and Canada than in other countries (e.g., Korea, Japan, and China), making it the weapon of choice for the offender. ...
... As shown in Table 2, the selected variables were measures of the setting, clothing, sexual behavior, wound location, stolen property, method location, and weapon (Salfati, 2000;Salfati & Dupont, 2006;Salfati & Haratsis, 2001;Salfati & Park, 2007;Santtila et al., 2001). Crime scene actions that are only more prevalent in serial homicide cases were not included 2 (e.g., controlling behaviors, such as gagging, blindfolding, and binding the hands and legs of the victim; see Hodgskiss, 2004;Salfati & Bateman, 2005;Sorochinski & Salfati, 2010). ...
The aim of the current study is to identify themes of crime scene behaviors in a sample of 487 Korean homicides and test whether these themes are linked to offender characteristics. A content analysis of police information was first conducted and then a multidimensional scale approach was used to identify themes in the homicide data. The exploratory thematic structure showed four factors that confirmed the instrumental/expressive themes as being useful in differentiating homicides: sex-arousal, cognitive, overkill-blood, and impulsive. These four themes were compared with the previous themes identified in Western studies of homicide. Finally, the current findings support the idea that there are relationships between crime scene behavior themes in homicide and offender characteristics.
... Few studies have examined how offending behaviours may change across series. Sorochinski and Salfati (2010) examined behavioural consistency and behavioural change patterns across the first three offences in homicide series. This study provided evidence that it is useful to look for behavioural consistency in terms of behavioural trajectories (e.g. ...
... escalating in degree or switching from one behavioural subtype to another) rather than isolated behaviours. Three additional studies (Hewitt and Beauregard 2014;Leclerc et al. in press;Lussier et al. 2008) used transition matrices to estimate the probability of behaviours used in the first crime to be repeated 1 Bateman and Salfati 2007;Bennell and Canter 2002;Bennell and Jones 2005;Bennell et al. 2009;Bouhana et al. 2014;Burrell et al. 2012Burrell et al. , 2015Canter et al. 1991;Deslauriers-Varin and Beauregard 2013;Ellingwood et al. 2013;Fox and Farrington 2014;Green et al. 1976;Grubin et al. 2001;Harbers et al. 2012;Hewitt and Beauregard 2014;Kearns et al. 2011;Leclerc et al. in press;Lussier et al. (2008); Markson et al. 2010;Melnyk et al. 2011;Salfati and Bateman 2005;Salfati et al. 2014;Salo et al. 2012;Santtila et al. 2004Santtila et al. , 2005bSanttila et al. 2008Slater et al. 2015;Sorochinski and Salfati 2010;Tonkin & Woodhams 2015;Tonkin et al. 2008Tonkin et al. , 2011Tonkin et al. , 2012aTonkin et al. , 2012bWinter et al. 2013;Woodhams and Labuschagne 2011;Woodhams and Toye 2007;Woodhams et al. 2007aWoodhams et al. , 2008 in subsequent crimes of persistent sexual offenders. The findings suggested that changes in offenders' behaviours occur in a fairly predictable manner as a function of the offender's level of self-control as well as situational constraints. ...
... When they started off with none to low control, they were most likely to escalate during this transition. In addition, offenders are least consistent in their second transition (from the second to third crime), which may be evidence of learning and choosing the most adaptive strategy for achieving their goal (Canter and Youngs 2003;Sorochinski and Salfati 2010). Finally, in their third transition (from the third to fourth crime), the consistency levels increased again, particularly, for offenders who exerted moderate or high levels of control. ...
Whilst investigative use of behavioural evidence to help link and solve serial offences has long been in use, the empirical and theoretical grounds for whether and how to use this evidence effectively have begun to emerge only in recent decades. The present study empirically tested (a) the potential for effectively differentiating between rape offence crime scenes using quantitative and qualitative distinctions within the behavioural dimensions of control, violence, and sexual activity, and (b) the extent to which redefining behavioural consistency more broadly to include dynamic trajectories of behavioural change may be more effective than limiting this definition to behavioural stability. Results confirmed that sexual offences can be successfully differentiated based on the specific degree and subtype of these behavioural dimensions present in each crime scene. The analysis of consistency and behavioural trajectories showed that whilst none of the offenders exhibited complete consistency across behavioural dimensions, a subsample of offenders remained fully consistent in at least one. Furthermore, of those who were not consistent, the vast majority followed an identifiable trajectory of change. Findings are discussed in the context of psychological theories of behavioural consistency as well as practical aspects of advancing the utility of behavioural linkage.
... Serial offenders and serial homicides have been the object of numerous studies over the last decades. Notwithstanding this extensive body of research (Canter & Youngs, 2009;Grubin, Kelly & Brusdon, 2001;Fritzon & Ridgway, 2001;Salfati, Horning, Sorochinski & Labuschagne, 2012;Salfati & Sorochinski, 2010), a thorough understanding of this violent act remains incomplete, partly due to the difficulty assessing the calculating nature of human behavior (Shoemaker, 2010). ...
... Recent studies (Sorochinski & Salfati, 2010), however, have shown that the current version of the model might not be the best application when applied to serial homicide cases. ...
... With a growing body of literature (Canter, 1994;Salfati & Canter, 1999, Salfati, 2003 highlighting the victim-offender interaction, emphasis is being placed in understanding the psychological underpinning of the identifiable behaviors observable at the crime scene (Canter & Youngs, 2012;Salfati, Horning, Sorochinski & Labuschagne, 2015;Sorochinski & Salfati, 2010). Behavioral themes have been suggested (Canter, 1994) to provide an informative model on victim's vulnerable "role" at the crime scene. ...
... Recent literature suggests that different 'styles' of homicide will most appropriately be reflected in the different types of behaviours committed by offenders during a crime and Salfati's (2010) study, specifically looking at the applicability of the framework for classifying crime scenes using a sample of South African homicide series in order to establish the generalisability of this approach. ...
... Thematic differentiation within these two subgroups of behaviours was tested as part of a recent study of serial homicides (Sorochinski & Salfati, 2010). 1 The results of the study showed that over 75% of offences could be classified into one of the distinguishing themes within each behavioural subgroup (i.e. pre-offence planning versus post-offence planning and goal-oriented wounding versus process-oriented wounding). ...
... There is, therefore, a great need to better understand the phenomenon within the South African context and establish whether what we know to date about serial homicide in other countries can be applied and used in the investigative efforts of the South African Police Service. The present study thus aims to test how the factors of planning and type of violence, suggested by Sorochinski and Salfati (2010) as described earlier, are manifested in a sample of South African serial homicides. ...
Recent literature suggests that different ‘styles’ of homicide will most appropriately be reflected in the different types of behaviours committed by offenders during the crime. In the last few years, there has been a move to standardise classification systems of single homicides and establish their cross-national generalisability. Literature on serial homicide to date has mostly centred on homicides occurring in the US. However, national differences due to factors such as culture, national identity, political, and socio-economic circumstances may decrease the applicability of these models or certain aspects thereof in other countries and thus must be evaluated. The present study tested the applicability in the South African context of a recently developed US-based serial homicide crime scene classification framework. Specifically, this study compared the thematic differentiation in planning and violent behaviours that the offenders engage in and how this differentiation compares with that in the US. The sample consisted of 25 homicides that were in total responsible for the murder of 267 victims. Results indicated that overall, the framework is useful and applicable in the South African sample, but important environmental and contextual constraints must be taken into account. Copyright © 2014 John Wiley & Sons, Ltd.
... Recently, Sorochinski and Salfati (2010) highlighted planning as a focus of highly cognitive behaviours. They surmised that planning comprised behaviours related to the timing and location of the homicide and its subsequent cover-up. ...
... Thus, it can be hypothesised that a change from one strategy to the other within this behavioural subgroup may be due to learning and experience. In the US sample (Sorochinski & Salfati, 2010), it was found that indeed most offenders who change their planning strategy across the series do so from first to second offence, supporting the learning hypothesis. Sorochinski et al. (2015) conducted a classification study to determine if the behaviours of South African offenders could be similarly differentiated into two distinct planning strategies. ...
... Keppel and Walter (1999), in their classification of sexual homicide offenders, differentiate between those offenders who planned both the rape and the murder from those who only planned the rape with the murder being a spontaneous act. In line with these theories, Sorochinski and Salfati (2010) found that offenders' behaviours at each crime scene could be reliably differentiated into either goal-oriented or process-oriented violence, but the offenders were least consistent in their wounding strategies (compared with other behavioural subgroups) because of high likelihood of situational factors forcing the change. In addition, it was found that offenders were more likely to change from goal oriented to process oriented than the vice versa, possibly, confirming the loss of control hypothesis. ...
Key to understanding the significance of behavioural evidence for linkage purposes is in establishing how consistently an offender displays the same or similar behaviours across their series. There have however to date been very few studies aiming at identifying salient components of offending behaviour that can be used reliably for linking individual crimes as part of a single series. In addition, studies that have been conducted have all dealt with serial homicide in the Western world and have been based on small samples of cases from each country. Some of the recent literature has started to disentangle some of these salient features, notably the victim, violence levels, control, and planning. The current study focused on evaluating the consistency of these features across series, using a sample of serial homicides from South Africa consisting of 30 offenders with a total of 283 victims and 235 crime scenes. Results indicate that the level of interaction with the victim may be influential to the stability or instability of offending patterns across the series. How offenders approach planning in their offence also showed a certain degree of consistency, with patterns of violence being the least consistent across the series of all components tested. Copyright © 2014 John Wiley & Sons, Ltd.
... These cues then become part of a fixed knowledge structure (also known as scripts) that will influence the commission of future offending behaviors. Therefore, as offenders learn from their previous experiences, they might try to commit different types of crime during the first few offenses, in order to determine which one(s) are more suited to their skills and preferences and are more likely to help them achieve their goal (e.g., Cusson 1993;Rossmo 2000;Sorochinski and Salfati 2010). Once successful, the offender can then start to reproduce or engage in a specific type of crime over time, which leads to a gradual specialization process. ...
... To date, empirical studies in the field of behavioral consistency have been conducted on a limited set of criminal behaviors and often on the most extreme forms of crime. Indeed, the focus of most studies has been on violent crimes, such as sexual offences (e.g., Sjöstedt et al. 2004;Woodhams, Grant, and Price 2007;Woodhams, Hollin, and Bull 2008), sexual assault (e.g., Davies 1992;Deslauriers-Varin 2013, 2014a, 2014bGrubin, Kelly, and Brunsdon 2001;Harbers et al. 2012;Lundrigan, Czarnomski, and Wilson 2010), rape (Davies, Wittebrood, and Jackson 1997;Santtila, Junkkila, and Sandnabba 2005;Labuschagne 2012a, 2012b), homicide (e.g., Bateman and Salfati 2007;Melnyk et al. 2011;Salfati and Bateman 2005;Santtila et al. 2008;Sorochinski and Salfati 2010), as well as sexual homicide (e.g., Schlesinger et al. 2010). The growing popularity of crime linkage, however, has led some researchers to explore the utility of crime linkage with a wider range of crime types, such as burglary (e.g., Bennell and Canter 2002;Bennell and Jones 2005;Bernasco 2008;Markson et al. 2010;Melnyk et al. 2011;Tonkin, Santtila, and Bull 2012;Toye 2007), car theft (e.g., Tonkin et al. 2008), and arson (Ellingwood et al. 2013;Santtila, Fritzon, and Tamelander 2004). ...
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... A couple of decades of BCL research on serial homicide has also deepened our understanding of SHOs consistency and distinctiveness across their homicide series. Most of the research has been conducted on data from the United States (Salfati & Bateman, 2005;Bateman & Salfati, 2007;Sorochinski & Salfati, 2010;Melnyk, Bennell, Gauthier, & Gauthier, 2011;, but some BCL research has also been conducted on data from South Africa (Salfati, Horning, Sorochinski, & Labuschagne, 2015) and Italy (Salo, Sirén, Corander, Zappalà, Bosco, Mokros, & Santtila, 2013; studies in present thesis). Themes of behaviour have, generally, been found to have higher consistency than individual behaviours. ...
... In one of the first empirical studies of behavioural consistency in serial homicide, Salfati and Bateman (2005) showed that SHOs demonstrated some consistency for instrumental and expressive themes over their series. Planning behaviour (both before and after the homicide) seems to be among the most consistent behaviours (Bateman & Salfati, 2007;Sorochinski & Salfati, 2010;Salfati et al., 2015). Interestingly, victim selection does not appear to be as consistent . ...
Behavioural crime linking refers to the practice of trying to tie two or more offences to the same offender using behaviour observable at the crime scene. It rests on the assumptions that offenders behave consistently enough from one offence to another, and distinctively enough from other offenders allowing offences to be successfully linked together. Conceptualised in the 70s, and developed methodologically with increased scientific rigour from the 90s, the last decade has seen a sharp rise in published studies on behavioural crime linking. From empirical validation of the underlying assumptions to mapping out practice and more ecologically valid tests of linkage accuracy, the field has developed considerably. Considering that investigating homicide is resource intensive, not to mention serial homicide, reliable and valid behavioural crime linking has the potential to aid and prioritise investigative avenues and help solve serial homicide.
Most studies on serial homicide have been carried out on North American samples. While some research has studied the consistency and distinctiveness of serial homicide offenders, few have empirically tested models of behavioural crime linking and linkage accuracy with serial homicide. Another shortcoming in behavioural crime linking research is the use of mostly serial cases to model crime linking, even though real crime databases include both serial and one-off offences. Some studies have tested the effect of added one-offs on the linkage accuracy of burglary and rape, but none so far the effect this would have on homicide. Additionally, while some studies have compared serial homicide offences to one-off homicides, none have tested whether it would be possible to predict whether a homicide belongs to a series or is a singular offence. Cognitive bias, especially confirmation bias or the expectancy effect, has been shown to have a considerable effect on crime investigation. No studies to date have explored the effect of such bias in behavioural crime linking.
The general aim of the thesis was to increase ecological validity of behavioural crime linking research, especially with regard to sampling choices and analyses that strive to answer questions relevant for homicide investigation. The main sample consisted of 116 Italian serial homicides, committed in 23 separate series of homicide. Additionally, information about 45 cases of hard-to-solve one-off homicide was gathered, coded, and added to the sample. Study I found seven behavioural dimensions of offending (e.g., sexually motivated homicides and aspects of control-behaviour) in line with previous research. Notably, also other motives than sexual were found in the killings. A majority of offences (63%) were correctly classified to their actual series in the predictive part of the study. Study II was an experiment that investigated whether knowledge of series membership increased perceived (coded) behavioural similarity in homicides committed by the same offender. While no support was found for a strong expectancy effect, the experimental task may have lacked in sufficient complexity, and replication is thus needed. Study III found several key differences between serial and singular homicides and was able to successfully use these differences to predict with good accuracy whether an offence was part of a series. Study IV combined all the advances in the methodology thus far and showed that behavioural crime linking was still viable even with a large proportion (10:1) of one-off homicides added into the sample. As a function of added one-off homicides, the specificity of the model worsened (more false positives), as did the proportion of offences belonging to a series found near the top of a ranked listing from more behaviourally similar to less behaviourally similar. Overall model accuracy remained good, though, further validating the practice of behavioural crime linking with more ecologically valid data.
The studies of the present thesis contribute to the methodology of behavioural crime linking research. Replication on local crime databases is needed to maximise the practical usefulness of the models in different jurisdictions. Going forward, a close-knit collaboration between researchers and practitioners is called for, to keep the research relevant for practice and to develop evidence-based practice. As we gain a clearer picture of the accuracy and error rate of behavioural crime linking models, their usefulness increase in both the criminal investigative phase and in the trial phase with behavioural crime linking being presented as expert evidence.
... It is conceded that not all necrophilic offenders will behave in the same manner, either in how they relate to the corpse sexually or how they dispose of that corpse once it can no longer fulfil its role in the necrophile's sexual fantasy. Indeed, as found by others in their study of serial homicide (see for example, Sorochinski & Salfati 2010), sexual homicidal offenders do not engage in the exact same rituals with each successive offence, although they are often behaviourally similar (Schlesinger et al 2010). In this case, whilst all victims were killed in the same manner, and the postmortem behaviours were similar, dressing, bathing and mimicking relationship behaviours with the corpses, the sexual element varied. ...
... Inconsistency of sexual activities with corpses is noted and, in so doing, reference is made to Sorochinski & Salfati 2010;Schlesinger et al 2010;Burgess et al 1986;Keppel 2000;and Boureghda et al 2011. In the methodology section and at the end of the discussion section it is explicitly noted that generalisations cannot be made from a single case. ...
In the relatively limited amount of scholarly literature examining necrophilia, there has been historical disagreement over the presence of sexual sadism in the sexual violation of the dead. A case study is presented here of necrophilia, in the context of serial homicide, which seeks to explore and clarify those arguments and ascertain whether there are inherently sadistic elements in this sexual paraphilia. In so doing, it determines the appropriate legal classification of necrophilia as either a sexual or property offence.
... The selection of crime scene action variables in the current study was made based on the robust results in both Western and Eastern studies. The researches were conducted in the United States (Salfati & Bateman, 2005;Sorochinski & Salfati, 2010), Belgium (Thijssen & Ruiter, 2011), Greece (Salfati & Haratsis, 2001), Canada (Salfati & Dupont, 2006), Finland (Santtila et al., 2001), Korea (Salfati & Park, 2007;Sea & Beauregard, 2017a), and Japan (Zaitsu, 2010). ...
... Both men and women did not use firearms to commit the murder. Sorochinski, Salfati, and Labuschagne (2015; see also Sorochinski & Salfati, 2010) explored two domains for local contextual differences: tool availability and physical environment and psychological factors. From this point, firearms (legal or illegal) may be more accessible in the United States and Canada than in other countries (e.g., Korea), making it the weapon of choice for the American or Canadian offender, but not the Korean one. ...
The comparison of the South Korean male and female homicide offenders’ characteristics and crime scene behaviours is presented in this study. A total of 537 cases of homicide offenders prosecuted in Korea between 2006 and 2010 were analyzed in terms of offenders’ characteristics, victim–offender interaction, places of crime, and crime scene actions. Significant differences between male and female offenders were revealed in prior criminal history, offenders’ personal characteristics, choice of victim, crime scene behaviours during and after the homicide, and choice of weapon. The parallel with the gender differences in homicides found in Western countries is discussed as well as the possible explanations for the gender-related characteristics found in this study.
... This concept has been corroborated by research using a "thematic" or offending style approach, which has shown that those who commit styles of crime that generally reflect higher levels of control, such as signs of premeditation and careful selection of the victim and crime location, are more consistent across offenses than offenders utilizing offense styles that exhibit less control in the behaviors they can influence (Bennell & Canter, 2002;A. Davies, 1992;Markson et al., 2010;Sorochinski & Salfati, 2010). This has led some to believe that there are different levels of consistency in offending that depend upon the style of crime the offender commits (K. ...
... The J coefficient suggests an inverse and potentially non-linear relationship between the number of crimes committed and offending style consistency, while the D Index suggests that offenders may become increasingly and significantly more consistent as they commit more crimes. It therefore remains unclear whether offenders become more consistent in behavior as they learn their strengths and gain expertise, as the personality psychology literature suggests (Caspi & Bem, 1990;Mischel, 1999), or if offenders change their behavior depending on what they learn in the field and adapt easily to environments suitable for different styles of offenses once they become more prolific in their criminal career (Blumstein et al., 1988;Harbers et al., 2012;Sorochinski & Salfati, 2010). Additional research examining the social, situational, and ...
This study evaluates the behavioral consistency in offending styles among a sample of serial burglars from the United States. Three popular specialization analyses—Jaccard’s coefficient, the forward specialization coefficient (FSC), and the Diversity (D) index—are used to compare if, and how much, variation exists in the behavior of serial burglars committing different styles of offenses, among the three analyses. Results show that there is variation across the analyses, with the FSC and D index suggesting serial burglars are relatively consistent in their burglary offense styles. However, burglars with organized and disorganized offense styles are more consistent in behavior across offenses than burglars who committed opportunistic and interpersonal style offenses. These findings have important methodological implications for criminological research, and practical implications for policing and crime linkage analysis.
... These cues then become part of a fixed knowledge structure (also known as scripts) that will influence the commission of future offending behaviors. Therefore, as offenders learn from their previous experiences, they might try to commit different types of crime during the first few offenses, in order to determine which one(s) are more suited to their skills and preferences and are more likely to help them achieve their goal (e.g., Cusson 1993;Rossmo 2000;Sorochinski and Salfati 2010). Once successful, the offender can then start to reproduce or engage in a specific type of crime over time, which leads to a gradual specialization process. ...
... To date, empirical studies in the field of behavioral consistency have been conducted on a limited set of criminal behaviors and often on the most extreme forms of crime. Indeed, the focus of most studies has been on violent crimes, such as sexual offences (e.g., Sjöstedt et al. 2004;Woodhams, Grant, and Price 2007;Woodhams, Hollin, and Bull 2008), sexual assault (e.g., Davies 1992;Deslauriers-Varin 2013, 2014a, 2014bGrubin, Kelly, and Brunsdon 2001;Harbers et al. 2012;Lundrigan, Czarnomski, and Wilson 2010), rape (Davies, Wittebrood, and Jackson 1997;Santtila, Junkkila, and Sandnabba 2005;Labuschagne 2012a, 2012b), homicide (e.g., Bateman and Salfati 2007;Melnyk et al. 2011;Salfati and Bateman 2005;Santtila et al. 2008;Sorochinski and Salfati 2010), as well as sexual homicide (e.g., Schlesinger et al. 2010). The growing popularity of crime linkage, however, has led some researchers to explore the utility of crime linkage with a wider range of crime types, such as burglary (e.g., Bennell and Canter 2002;Bennell and Jones 2005;Bernasco 2008;Markson et al. 2010;Melnyk et al. 2011;Tonkin, Santtila, and Bull 2012;Toye 2007), car theft (e.g., Tonkin et al. 2008), and arson (Ellingwood et al. 2013;Santtila, Fritzon, and Tamelander 2004). ...
Crime specialization is one of the most researched and often-debated criminal career parameters. To date, the concept of specialization has been approached mainly from a static viewpoint whereby crime specialization and criminal versatility have been conceptualized as two opposite end of a continuum. Emerging research based on longitudinal data, however, has led to the emergence of a dynamic-oriented perspective where specialization and versatility can occur during one’s career. In this essay, the evolution of the concept of crime specialization is highlighted along with associated theoretical, conceptual, methodological, and empirical issues stemming from this gradual change. Policy implications and directions for future research on the development of criminal careers are highlighted.
... Likewise, behaviours committed at the crime scene including sexual contact and the physical treatment of the victim (such as wounding), have been shown to be less consistent across offence series (Park, 2009;Santtila et al., 2008;Sorochinski & Salfati, 2010). Taken together, behaviours occurring prior to the offence have been shown to be accurate components for linking cases. ...
... To date, varying degrees of breadth and focus on offence behaviours have been employed by researchers to identify key features of a crime (Goodwill, Alison & Beech, 2009;Grubin, Kelly, & Brunsdon, 2001;Sorochinski & Salfati, 2010). Importantly, some studies subdivided offenders' MO into aspects based on temporal sequencing of behaviours (Santtila et al., 2005;Santtila et al., 2008), allowing for a nuanced understanding of what is occurring at various stages of the offense. ...
The present study investigated behavioural consistency across sexual offending. Variations in behavioural consistency may arise from an increased influence of situational and contextual aspects. However, there is paucity of research exploring variations in behavioural consistency relative to the temporal sequence of the behaviour (e.g., occurring prior to or during the offence). A sample of 49 male serial stranger sexual offenders responsible for 147 offences across four temporal phases of a sexual offence was used in the current study. For each offence, four crime phases were identified: 1) pre-crime, 2) victim selection, 3) approach, and 4) assault. Behavioural consistency within and across offence series were examined utilizing Jaccard’s Coefficient and Receiver Operating Characteristics (ROC). Results indicated a high degree of behavioural consistency across all crime aspects; behaviours that were more dependent on situational influences were inherently less predictable and demonstrated to be less consistent. Further, increased behavioural consistency was associated with offender characteristics of a more stable nature. The implications of these findings are discussed.
... A small proportion of offenders are responsible for the majority of crime (Clarke & Eck, 2003;Tilley & Laycock, 2002) and so it is unsurprising that government policy frequently puts pressure on the police to focus their investigative efforts on prolific offenders (Woodhams & Toye, 2007). Identifying serial crimes and linking these offences to individual offenders is a crucial part of police work (Bennell, Jones, & Melnyk, 2009;Santtila, Fritzon, & Tamelander, 2004;Sorochinski & Salfati, 2010;Yokota & Watanabe, 2002) and is used to streamline investigative efficiency (Santtila, Junkkila, & Sandnabba, 2005), pool evidence (Bennell et al., 2009) and/or narrow the search for the offender (eg, through geographic profiling and/or offender profiling (Canter & Larkin, 1993;Santtila et al., 2004;Santtila, Häkkänen, & Fritzon, 2003)). ...
... Offenders must therefore commit their offences in a consistent but distinctive manner for case linkage to be feasible (Woodhams et al., 2007). Academic exploration of case linkage (eg, testing the principle of behavioural consistency) has traditionally concentrated on serious offending (such as rape and murder) (eg, Bateman & Salfati, 2007;Hazelwood & Warren, 2003;Salfati & Bateman, 2005;Sorochinski & Salfati, 2010), however, there is a growing body of research exploring how case linkage can be used to link volume crimes including vehicle crime (Tonkin, Grant, & Bond, 2008) and burglary (Bennell & Jones, 2005;Markson, Woodhams, & Bond, 2010). Case linkage in real-world investigative settings is typically conducted by crime analysts working within police forces and other specialist crime agencies (Woodhams & Toye, 2007). ...
Comparative Case Analysis (CCA), typically conducted by crime analysts, uses crime scene behaviours to try to identify series of crimes committed by the same offender. Accurate identification of series of offences allows the police to pool resources and evidence, thereby boosting the potential to identify and apprehend the offender. This paper discusses the results of a survey of a sample of crime analysts working in two UK police forces about their views and experiences of CCA. The results focus on how CCA is conducted, what evidence and information is considered, and how useful CCA is to criminal investigation. Suggestions for how CCA might be developed further are also included.
... • Some linkage studies have excluded from their analyses very common and also infrequent, or rare behaviors (e.g., Grubin et al., 2001;Sorochinski & Salfati, 2010;Woodhams, Hollin, & Bull, 2008;Woodhams & Toye, 2007). * However, in practice, an atypical behavior could be crucial in linking a series together, if that behavior was exhibited in a consistent fashion by an offender. ...
... * However, in practice, an atypical behavior could be crucial in linking a series together, if that behavior was exhibited in a consistent fashion by an offender. • At least some serial offenders appear to behave less consistently than others (e.g., Bootsma & Eshof, 2006;Deslauriers-Varin & Beauregard, 2010;Grubin et al., 2001;Harbers, Deslauriers-Varin, Beauregard, & van der Kemp, 2012;Sorochinski & Salfati, 2010). This presents a problem for practitioners who, at present, have no evidence-based means of determining whether the series with which they are concerned is the work of a consistent or inconsistent offender. ...
... Landau (2000) further stressed the necessity for a stronger emphasis in future research on cross-national comparisons that would be of value to increasing our knowledge of homicide studies in different countries. Numerous studies have started to test thematic classifications across different national samples (Salfati & Dupont, 2006;Salfati & Haratsis, 2001;Salfati & Park, 2007), and in serial homicide (Bateman & Salfati, 2007;Salfati & Bateman, 2005;Sorochinski & Salfati, 2010;Trojan & Salfati, 2010), but to date there are no studies that empirically compare serial homicide in different national contexts, using actual police files. ...
... Canter, 1995;Canter, 2000;Douglas & Munn, 1992;Egger, 2002;Hickey, 2006;Holmes & Holmes, 1998;Keppel & Walter, 1999;Kraemer, Lord, & Heilbrun, 2004;Kocsis & Irwin, 1998;Pakhomou, 2004;Ressler, Burgess, Douglas, Hartman, & D'Agostino, 1986;Schlesinger, 2002). In recent years, studies with a more empirical focus have been provided, testing some of these theoretical ideas (Bateman & Salfati, 2007;Canter, Alison, Alison, & Wentink, 2004;DeFronzo, Ditta, Hannon, & Prochnow, 2007;Salfati & Bateman, 2005;Santtilla et al., 2008;Sorochinski & Salfati, 2010;Trojan & Salfati, 2010). These recent studies have enabled an improved research agenda with more effective methods to analyse serial homicide offenders and their victims. ...
There is an abundance of literature on serial homicide from a Western perspective that outlines operational definitions, types of offenders and how they prey upon their victims. However, currently, there is a lack of studies that compare serial homicide in different countries. The current study aims to give an overview of the demographics of serial homicide offenders and victims in South Africa and compare these to the demographics of offenders and victims from other currently available empirical studies of other countries. The sample consisted of 33 out of the total 54 solved series in South Africa between 1936–2007, which includes a total of 33 offenders, 302 victims, and 254 crime scenes. Results of the sample as a whole showed that South African serial homicide offenders are similar to offenders in other countries in terms of their actions at the crime scene and victim choice, with some notable exceptions. Additional analysis looked at the offender's consistency of targeting certain types of victims across their homicide series in comparison with the patterns of serial homicide offenders in other countries. Copyright © 2014 John Wiley & Sons, Ltd.
... As offenders learn from their previous experiences, they try out various strategies at different times and places during the first few offences in order to determine what strategy works best for successfully achieving their goal (e.g. Cusson, 1993;Rossmo, 2000;Sorochinski & Salfati, 2010). Once a successful strategy has been determined, the offender may decide to limit his repertoire to this offending strategy, which leads to the consistent use of specific behaviours or offence sites (Lundrigan et al., 2010). ...
... For example, although they might still agree on the conceptual definition of serial offenders previously suggested (i.e. two crimes committed on separate occasions), researchers investigate consistency with a sample of serial offenders having committed at least three (e.g. Bennell & Jones, 2005;Melnyk, Bennell, Gauthier, & Gauthier, 2011;Sorochinski & Salfati, 2010) or sometimes five or more (e.g. Bateman & Salfati, 2007;Melnyk et al., 2011) offences at different times and locations. ...
... This model has been tested in and validated across a multitude of samples of sexual offenses (e.g. Fritzon & Ridgway, 2001;Horning et al., 2015;Sorochinski & Salfati, 2010). Figure 1 summarizes the possible application of the model to technology-facilitated sexual violence behaviors. ...
In recent years, a new type of interpersonal crime has emerged where victimization happens through the use of technology and/or cyber space. The legal, law enforcement, as well as social scientific research fields have yet to fully grasp the scope of this modern crime type. In this paper, we review what is currently known on the issue with 5 Ws and 1 H approach, in terms of their current understanding, prevalence, victimization patterns, motivations, and relationship between violence in the cyberspace and offline. We end with a proposal for future directions and argue that a useful framework for researching this type of crime may be the interpersonal model first developed within the investigative psychology field for the classification and profiling of sexually violent offenses.
... La consistencia conductual en delincuentes seriales ha sido estudiada en el caso de homicidios (Salfati & Bateman, 2005;Bateman & Salfati, 2007;Sorochinski & Salfati, 2010;Salfati, Horning, Sorochinski & Labuschagne, 2015), intrusión en propiedades con fines de robo (Bouhana, Johnson & Porter, 2016;Fox & Farrington, 2016), y agresores sexuales (Lundrigan, Czarnomski, & Wilson, 2010;Harbers, Deslauriers-Varin, Beauregard & Kemp, 2012;Deslauriers-Varin & Beauregard, 2013, 2014a, 2014bHewitt & Beauregard, 2014;Oziel, Goodwill & Beauregard, 2015). En general, estos estudios concluyen, de una forma metodológicamente aceptable, que los delincuentes seriales tienden a repetir sus conductas crimen tras crimen (Janosch & Soto, 2018; Janosch, Pérez-Fernández & Soto-Castro, 2018a y 2018b; Janosch, Pérez-Fernández & Soto-Castro, 2020; Pérez-Ramírez, Giménez-Salinas, González-Álvarez, Soto-Castro, 2021). ...
Propósito: Estudiar la consistencia en las conductas de los agresores sexuales desconocidos y seriales en la escena del crimen, y la influencia de los factores situacionales. Método: Se analizan las conductas en la escena del crimen de 18 agresores sexuales desconocidos y seriales, que cometieron al menos 54 agresiones sexuales. Se han correlacionado con factores situacionales. Se ha estudiado también la consistencia de cada una de esas conductas. Resultados: Algunas conductas de los delincuentes están influidas por factores situacionales y, a la inversa, algunos factores situacionales pueden estar influidos por tales conductas. Algunas conductas que, prima facie, no están influenciadas por los factores situacionales son consistentes. Una excepción son las conductas sexuales del delincuente. Conclusión: Este análisis confirma, aunque limitadamente, relaciones conductuales esperables, pero nunca antes estudiadas, en una muestra española de agresores sexuales seriales y desconocidos.
... La consistencia conductual en delincuentes seriales ha sido estudiada en el caso de homicidios (Salfati & Bateman, 2005;Bateman & Salfati, 2007;Sorochinski & Salfati, 2010;Salfati, Horning, Sorochinski & Labuschagne, 2015), intrusión en propiedades con fines de robo (Bouhana, Johnson & Porter, 2016;Fox & Farrington, 2016), y agresores sexuales (Lundrigan, Czarnomski, & Wilson, 2010;Harbers, Deslauriers-Varin, Beauregard & Kemp, 2012;Deslauriers-Varin & Beauregard, 2013, 2014a, 2014bHewitt & Beauregard, 2014;Oziel, Goodwill & Beauregard, 2015). En general, estos estudios concluyen, de una forma metodológicamente aceptable, que los delincuentes seriales tienden a repetir sus conductas crimen tras crimen (Janosch & Soto, 2018; Janosch, Pérez-Fernández & Soto-Castro, 2018a y 2018b; Janosch, Pérez-Fernández & Soto-Castro, 2020; Pérez-Ramírez, Giménez-Salinas, González-Álvarez, Soto-Castro, 2021). ...
Filiación Institucional (1) Resumen Propósito: Estudiar la consistencia en las conductas de los agresores sexuales desconocidos y seriales en la escena del crimen, y la influencia de los factores situacionales. Método: Se analizan las conductas en la escena del crimen de 18 agresores sexuales desconocidos y seriales, que cometieron al menos 54 agresiones sexuales. Se han correlacionado con factores situacionales. Se ha estudiado también la consistencia de cada una de esas conductas. Resultados: Algunas conductas de los delincuentes están influidas por factores situacionales y, a la inversa, algunos factores situacionales pueden estar influidos por tales conductas. Algunas conductas que, prima facie, no están influenciadas por los factores situacionales son consistentes. Una excepción son las conductas sexuales del delincuente. Conclusión: Este análisis confirma, aunque limitadamente, relaciones conductuales esperables, pero nunca estudiadas, en una muestra española de agresores sexuales seriales y desconocidos. Palabras Clave Agresión sexual, desconocido, decisiones conductuales, situación, consistencia conductual. Abstract Purpose: To study the consistency in crime scene behaviors of unknown and serial sexual offenders and the influence of situational factors. Methods: The crime scene behaviors of 18 unknown and serial sexual offenders, who committed at least 54 sexual assaults, were analyzed. They have been correlated with situational factors. The consistency of each of these behaviors was also studied. Results: Some offenders' behaviors are influenced by situational factors and, conversely, some situational factors may be influenced by such behaviors. Some behaviors that, prima facie, are not influenced by situational factors are consistent. An exception is offender sexual behaviors. Conclusion: This analysis confirms, albeit to a limited extent, expected but never studied behavioral relationships in a Spanish sample of serial and unknown sex offenders.
... Identifying crime series, and attributing these to a single offender/group of offenders, is essential for police investigators (Bennell et al., 2009;Sorochinski & Salfati, 2010) as it allows them to implement more efficient investigative strategies (Labuschagne, 2012) such as pooling information from multiple crime scenes to generate investigative leads (Bennell et al., 2009). Links between offences can be established using forensic evidence (such as DNA or footwear), however, such evidence is not always present at a crime scene (Ewart et al., 2005). ...
Research has shown that the majority of offences are committed by a minority of offenders. Therefore, any method to help identify prolific/serial offenders is of benefit to the police. Behavioural Crime Linkage (BCL) is a method of identifying series of offences committed by the same person(s) using the behaviour displayed during the offence. This can include, but is not limited to, target selection, control and weapon use, approach, property stolen, and temporal and spatial trends. This chapter will explain the theoretical framework for BCL and common methods for testing the accuracy of this method (e.g. logistic regression, Receiver Operating Characteristic
). The chapter will then outline how BCL has been applied in robbery. It will discuss how the success of BCL is influenced by factors such as type of location (e.g. urban versus rural) and group offending
(e.g. can you link offences committed by groups?). This chapter will draw heavily on the PhD research of the author but will cite other literature (e.g. evidence to support the theoretical framework for BCL) where relevant.KeywordsBehavioural crime linkageCrime linkageRobbery
... Serial murderers' motives could evolve with a single murder as well throughout a series of Regardless of the motive, serial killers commit their crimes because they want to. The exception to this would be the few offenders who suffer from a severe mental illness.Sorochinski and Salfati (2010) applied the consistency hypothesis in the development of typology definitions. They hypothesised that since people (in general) do not behave randomly, it is reasonable to expect some degree of consistency in a killer's behaviours as well. In the third edition of their work,Holmes and Holmes (2010) classified serial murderers in accorda ...
A PSYCHOBIOGRAPHY OF THE SERIAL KILLER: JOHN WAYNE GACEY
... While those who commit serial offenses are in the minority of sexual offenders as a group, misidentifications and wrongful convictions for single crimes within a series appear more common than would be expected by chance (67 out of 362 DNA exonerations; Johnson, 2020). An important concept, highlighted by Johnson, that has been at the core of many investigative psychology research studies in the past 30 years is the concept of "linkage blindness" (e.g., Bateman & Salfati, 2007;Canter et al., 2003;Salfati, 2008;Sorochinski & Salfati, 2010Woodhams et al., 2007)-when multiple related assaults are not readily recognized as constituting a series of offenses committed by the same individual. Often, such "blindness" occurs because investigators do not recognize the behavioral similarities across crimes that would suggest they were committed by the same person, or because there actually was little to no such consistency across their crimes. ...
This article reviews the recently published book by M. B. Johnson-Wrongful conviction in sexual assault: Stranger rape, acquaintance rape, and intra-familial child sexual assaults. The focus of the book is on the unique combination of factors specifically within sexual crime investigation and legislation that lead to the overrepresentation of this type of crimes within wrongful convictions. The book presents a detailed analysis of social context, and historical backdrop specific to wrongful convictions in sexual crimes. It is a highly informative and well-written book.
... In spite of a number of limitations, the authors concluded that there is little support for the consistency and homology assumptions. Using multidimensional scaling in a study of serial homicide cases, Sorochinski and Salfati (2010) suggested crime linkage using clusters of behaviors as opposed to single behaviors might demonstrate more consistency and homology across crimes. ...
Knowledge management (KM) is a critical organizational asset predicated upon a knowledge-based perspective of the firm that emphasizes identification, sharing, and exploitation of knowledge assets. Profiling practitioners, constituting a community of practice (CoP, are compared to empiricists associated as a community of interest (CoI). The CoP operates using tacit knowledge whereas the CoI codifies knowledge to make it explicit. Within criminal profiling the CoI are severely critical of the tacit methods and typologies utilized by the CoP with the consequence being empirical divergence from practice. A research agenda focused upon a multidisciplinary approach to criminal profiling, combining the CoP and CoI paradigms is needed to bridge the gap and settle questions of criminal profiling efficacy and contribute to theory.
... Patterns of behavioural consistency and change during the commission of multiple killings were also investigated using Multidimensional Scaling by Sorochinski and Salfati [24]. They reported a thematic differentiation in the cognitive strategies used by serial killers such as offender-victim interaction, planning and wounding. ...
... Patterns of behavioural consistency and change during the commission of multiple killings were also investigated using Multidimensional Scaling by Sorochinski and Salfati [24]. They reported a thematic differentiation in the cognitive strategies used by serial killers such as offender-victim interaction, planning and wounding. ...
This study explores the application of the FBI's organised-disorganised classification to North-American and European male serial killers. Adopting the same method as Taylor, Lambeth, Green, Bone and Cahillane's 2012 study, 52 crime scene criteria were used to categorise the murders committed by 25 male European and 25 male North-American serial killers. Applying content analysis, murders committed were dichotomously coded for the presence or absence of crime scene criteria using numerous secondary sources. Two separate agglomerative hierarchical cluster analyses using Ward's method as the clustering algorithm formed two clusters for the North-American and two for the European serial killers. There were differences in the crime scene criteria for clusters between North-American and European serial murders. The 'bottom-up' approach resulted in clusters from the crime scene criteria demonstrating that there are problems associated with classifying traits as simply organised and disorganised. All clusters comprised of a degree of core organised traits-consistent with Canter, Alison, Alison and Wentink's (2004) assumption that all serial killings require a degree of organisation. Further examination of frequency of occurrence measures suggests there are subtle but inherent differences between the MO of North American and European serial killers.
... La agrupación de las temáticas conductuales aparecidas en la EC en violencia expresiva e instrumental facilita la comprensión del tipo de personalidad del autor, su motivación y su consistencia comportamental, al existir diversos crímenes, facilitando en conjunto su aprehensión (Horning et al., 2010;Salfati, 2000;Salfati y Bateman, 2007;Salfati y Canter, 1999;Salfati y Dupont, 2006;Salfati y Haratsis, 2001;Sorochinski y Salfati, 2010;Thijssen y De Ruiter, 2011). ...
El homicidio en la pareja, considerado un problema social, no ha sido analizado en España en relación a la escena del crimen (EC). La presente investigación aborda el tipo de violencia ejecutada, instrumental vs. expresiva, en la EC de asesinatos, homicidios o tentativas y sus diferencias en función del sexo del homicida. A partir de una muestra formada por 322 casos extraídos de sentencias judiciales firmes mediante el Protocolo de Análisis del Crimen Violento en Homicidios Familiares, se analizó la conciencia forense, la estructuración y la conducta criminal. Los resultados apoyan estudios precedentes desarrollados en otros países mostrando el predominio de comportamientos expresivos en homicidios entre los miembros de la pareja sin existir diferencias significativas en función del sexo de los agresores, si bien aparece un mayor uso de las conductas de apuñalamiento y envenenamiento en mujeres homicidas.
... A number of studies have found evidence for the assumptions of crime linkage in serial crime (for a review of the research to date on behavioural crime linkage, see Bennell et al., 2014). While serial homicide has been studied less than, for example, rape, a few studies have found serial homicide offenders to be somewhat consistent in their behaviour over the course of their series (Bateman and Salfati, 2007;Salfati and Bateman, 2005;Salfati et al., 2015;Santtila et al., 2008;Sorochinski and Salfati, 2010). ...
Purpose
– The purpose of this paper is to explore the differences (if any) between serial and hard-to-solve one-off homicides, and to determine if it is possible to distinguish the two types of homicides based on offence behaviours and victim characteristics.
Design/methodology/approach
– A sample of 116 Italian serial homicides was compared to 45 hard-to-solve one-off homicides. Hard-to-solve one-off homicides were defined as having at least 72 hours pass between when the offence came to the knowledge of the police and when the offender was caught. Logistic regression was used to predict whether a killing was part of a series or a one-off offence.
Findings
– The serial killers targeted more strangers and prostitutes, displayed a higher level of forensic awareness both before and after the killing, and had more often an apparent sexual element in their offence. Conversely, the one-off homicides were found to include more traits indicative of impulsive and expressive behaviour. The model demonstrated a good ability (AUC=0.88) to predict whether a homicide belonged to the serial or one-off category.
Research limitations/implications
– The findings should be replicated using local homicide data to maximise the validity of the model in countries outside of Italy.
Practical implications
– Being able to distinguish between serial and one-off homicides based on information available at a new crime scene could be practically useful for homicide investigators managing finite resources.
Originality/value
– Studies comparing serial homicides to one-off homicides are scarce, and there are no studies explicitly trying to predict whether a homicide is an isolated case or part of a series.
... In the last type of approach, crime series clustering, all the clusters are found simultaneously. 8,[27][28][29][30][31][32][33][34][35] One of the earliest approaches we know of for clustering crimes is that of Dahbur and Muscarello, 29 who used a neural network approach. (This method had some serious flaws that required extensive heuristic post-processing after the clusters were created, but aimed at solving the more general problem of crime clustering.) ...
One of the most challenging problems facing crime analysts is that of identifying crime series, which are sets of crimes committed by the same individual or group. Detecting crime series can be an important step in predictive policing, as knowledge of a pattern can be of paramount importance toward finding the offenders or stopping the pattern. Currently, crime analysts detect crime series manually; our goal is to assist them by providing automated tools for discovering crime series from within a database of crimes. Our approach relies on a key hypothesis that each crime series possesses at least one core of crimes that are very similar to each other, which can be used to characterize the modus operandi (M.O.) of the criminal. Based on this assumption, as long as we find all of the cores in the database, we have found a piece of each crime series. We propose a subspace clustering method, where the subspace is the M.O. of the series. The method has three steps: We first construct a similarity graph to link crimes that are generally similar, second we find cores of crime using an integer linear programming approach, and third we construct the rest of the crime series by merging cores to form the full crime series. To judge whether a set of crimes is indeed a core, we consider both pattern-general similarity, which can be learned from past crime series, and pattern-specific similarity, which is specific to the M.O. of the series and cannot be learned. Our method can be used for general pattern detection beyond crime series detection, as cores exist for patterns in many domains.
... Prior studies used subsamples in order to test serial violent crime classification systems Salfati & Bateman, 2005;Sorochinski & Salfati, 2010). By eliminating crimes within a series, important information may be lost as offenders may change patterns and develop as series progress (Salfati, 2008). ...
This current study assessed the value of the Interpersonal Model in differentiating serial homicide offences in South Africa, notably in terms of how the offender may display behavioural patterns that are indicative of them dealing with the victim as a Person, an Object, or a Vehicle. The sample consisted of 302 offences committed by 33 offenders that occurred from 1953 to 2007 in South Africa. Multidimensional scaling analysis was used to test the Interpersonal Model and results indicated that crime themes did not directly correspond to the threefold model. Instead, two crime scene types were present: Victim as Object (where the focus was on tangible gains, interaction with the victim throughout the phases of the crime was limited, and victims included men and live women) and Victim as Vehicle (where the victim might be construed as a conduit through whom the offender could realise their specific psychological needs, the interaction was extensive, and victims tended to be vulnerable). South African serial homicides did not appear to have a specific sub-theme of Victim as Person, suggesting that the themes engaged in centred more on instrumentally focused actions but in qualitatively different ways. However, victim types were integral to the overall behavioural model. Using the Victim as Object/Vehicle dichotomy, 85.7% of the offences could be seen to engage dominantly in one of the two patterns at the crime scene. This not only supported the results of a twofold model, but having these many offenders showing a dominant crime scene type also shows that the model is an excellent representation of serial homicide offending in South Africa. Copyright © 2014 John Wiley & Sons, Ltd.
... Identifying serial crime and linking these offences to a single offender is a crucial part of police work (Bennell, Jones, & Melnyk, 2009;Santtila, Fritzon, & Tamelander, 2004;Sorochinski & Salfati, 2010;Yokota & Watanabe, 2002). Establishing that a number of offences are attributable to the same person supports the implementation of efficient and productive investigative strategies (Labuschagne, 2012;Santtila, Junkkila, & Sandnabba, 2005), for example, pooling information from all the crime scenes (Bennell et al., 2009), which can lead to faster identification and apprehension of the offender and/or strengthening the evidential case for court (Woodhams, Bull, & Hollin, 2007a). ...
Case linkage uses crime scene behaviours to identify series of crimes committed by the same offender. This paper tests the underlying assumptions of case linkage (behavioural consistency and behavioural distinctiveness) by comparing the behavioural similarity of linked pairs of offences (i.e. two offences committed by the same offender) with the behavioural similarity of unlinked pairs of offences (i.e. two offences committed by different offenders). It is hypothesised that linked pairs will be more behaviourally similar than unlinked pairs thereby providing evidence for the two assumptions. The current research uses logistic regression and receiver operating characteristic analyses to explore which behaviours can be used to reliably link personal robbery offences using a sample of 166 solved offences committed by 83 offenders. The method of generating unlinked pairs is then refined to reflect how the police work at a local level, and the success of predictive factors re‐tested. Both phases of the research provide evidence of behavioural consistency and behavioural distinctiveness with linked pairs displaying more similarity than unlinked pairs across a range of behavioural domains. Inter‐crime distance and target selection emerge as the most useful linkage factors with promising results also found for temporal proximity and control. No evidence was found to indicate that the property stolen is useful for linkage. Copyright © 2012 John Wiley & Sons, Ltd.
... Such a strategy could easily lead to a more dispersed geographical pattern of activity than would be expected for less active offenders who would not be so concerned that their activity would attract police attention in a particular geographical area. Further research would be necessary to test this hypothesis more directly, and to establish more precisely which categories of behaviours may gain or lose in consistency as series length increases, since different mechanisms are likely to be implicated in different aspects of offence behaviour (e.g., learning processes; see Sorochinski & Salfati, 2010, for a discussion in the context of serial homicide; or ecological constraint; see the discussion below). ...
PurposeBehavioural crime linkage is underpinned by two assumptions: (a) that offenders exhibit some degree of consistency in the way they commit offences (their modus operandi [MO]); and, (b) that offenders can be differentiated on the basis of their offence behaviour. The majority of existing studies sample at most three crimes from an offender's series of detected crimes and do not examine whether patterns differ across offenders. Here, we examine patterns observed across the entire detected series of each sampled offender, and assess how homogeneous patterns are across offenders. Methods
Using a non-parametric resampling approach, we analyse the entire crime series of 153 prolific burglars to determine if they exhibit consistency and specificity in the way they commit offences. ResultsFindings suggest that offenders exhibit consistency in the way they commit offences. With respect to specificity, our results suggest that patterns are not homogeneous across offenders or the type of MO considered – some offenders exhibit more specificity than do others, and offenders are more distinctive for some aspects of their MO (particularly spatial choices) than they are for others. Conclusions
The findings provide support for the underlying principles of crime linkage, but suggest that some aspects of an offender's MO either conform to a common preference, or are perhaps more influenced by situational factors than stable scripted preferences. That some offenders fail to demonstrate sufficient specificity for accurate linkage suggests that identifying which crimes are likely to be the work of offenders who display more specificity a priori constitutes one challenge for future research of this kind.
E tanulmányban arra a kérdésre keressük a választ, mivel tehető könnyebbé, biztosabbá, megbízhatóbbá a bűncselekmények összekapcsolása. Az egyik megoldást a profilalkotással, konzisztenciával kapcsolatos kutatások eredményei jelenthetik, másik oldalról pedig az elemző- értékelő munka igénybevétele, szoftveres támogatása és kutatásokra támaszkodó fejlesztése. Minél megbízhatóbb kutatási eredményeket tudnak alapul venni a rendvédelmi szervek és az elemző egységek, annál nagyobb hatékonysággal végezhetik munkájukat a sorozatjelleg megállapításakor és vizsgálatakor. Tanulmányunkban áttekintjük a bűncselekmények összekapcsolásával kapcsolatos legfontosabb kutatási eredményeket, valamint betekintést nyújtunk gyakorlati bevezetésük lehetőségeibe. Publikációnk végén pedig felvetünk néhány lehetséges kutatási témát, amelyekkel modernizálható lenne a hazai elemző-értékelő tevékenység, illetve az elektronikus Modus Operandi Nyilvántartás.
In the decade since the publication of the first edition of The Cambridge Handbook of Forensic Psychology, the field has expanded into areas such as social work and education, while maintaining the interest of criminal justice researchers and policy makers. This new edition provides cutting-edge and comprehensive coverage of the key theoretical perspectives, assessment methods, and interventions in forensic psychology. The chapters address substantive topics such as acquisitive crime, domestic violence, mass murder, and sexual violence, while also exploring emerging areas of research such as the expansion of cybercrime, particularly child sexual exploitation, as well as aspects of terrorism and radicalisation. Reflecting the global reach of forensic psychology and its wide range of perspectives, the international team of contributors emphasise diversity and cross-reference between adults, adolescents, and children to deliver a contemporary picture of the discipline.
This chapter explores the types of behaviour seen in sex offending. It covers how behaviour has been used to create typologies of offending, as well as how both internal factors – such as fantasy and offender characteristics, and external factors – such as the number of offenders present and the cultural influence on behaviour – can affect sex offender behaviour. It also explores how behaviour can be conceptualised as a pattern demonstrated across a series of offences, and the factors that can affect the consistency of this behaviour. Finally, this chapter outlines how our understanding of sex offender behaviour can contribute to the investigation, assessment, management, and treatment of sex offenders.
The majority of geographical profiling research focuses on the relationship between offender and location, which works particularly well when a burial site is known. In real-world investigations, however, burial or dump sites are often not known. The aim of the current paper is to outline a relatively under-used method of geographic profiling: Winthropping. While the method has been around for several decades, few studies have provided any research findings using it. There are two likely reasons for Winthropping being under-used: first, it has not been clearly, theoretically explained; second, given its relative novelty, it may not be immediately clear how to use it in research and real-world scenarios. The current paper outlines several key psychological (e.g., satisficing and affordances) and criminological (e.g., rational choice theory and crime geometry) theories that may explain why Winthropping works. Case studies are provided, and a methodological approach (matrix forecasting) is then provided to show how it could work in research practice and real-world applications. Overall, Winthropping is deemed to be highly useful, and it is hoped that experts in the field will begin developing this tool for wider, applied use.
Purpose
While behaviour sequence analysis (BSA) is popular, it is not without limitations, namely, the level of detail required and time taken to run analyses; therefore, this paper aims to outline a novel method, using 30 serial homicide cases as a worked example.
Design/methodology/approach
Temporal analysis methods are becoming increasingly popular in applied forensic and criminological research. In recent years, BSA has become a widely used approach.
Findings
Waypoint sequencing provides a streamlined version of the traditional BSA approach, allowing for fewer behaviours to be included and providing a clearer overview of the main behaviours of interest.
Practical implications
Waypoint sequencing is shown in the current paper through serial killer research to show how to conduct the analyses and how it is effective in current investigations by expediting the process and allowing quicker analysis to facilitate current investigations.
Originality/value
The current research provides a novel approach to sequence analysis that is more useful in applied settings as it requires fewer behaviours or events than traditional BSA.
Serial homicide for personal gratification is often commonly assumed to be driven by an underlying psychiatric compulsion, characterized by loss of control. This article briefly summarizes the behavioral science literature on serial homicide before then focusing on such behavior as a potential form of deviant leisure, which, because of the leisure criterion of relative autonomy, presents challenges to assumptions that killing is primarily an uncontrollable compulsion. Specifically, the case of Ted Bundy, one of the most prolific and well-known American serial sexual murderers, was analyzed to explore whether or not leisure concepts were embedded within interview content and forensic case documents; and if so, how such concepts may have functioned within a homicidal behavior process. Analysis focused on identifying potential leisure-related concepts embedded within transcripts of first-person interviews of Bundy conducted by Michaud and Aynesworth (2000 Michaud, S. G., & Aynesworth, H. (2000). Ted Bundy: Conversations with a killer—the death row interviews. Irving, TX: Authorlink Press. [Google Scholar]), while subsequently using forensic documents from victim cases to classify homicidal activities according to basic categories of the Leisure Behavior Inventory (Ragheb, 1980). Findings provide unique insights into the complex motivations and behaviors associated with serial murder.
In the 4 decades since offender profiling (OP) was established, hundreds of journal articles, books, book chapters, reports, and magazine articles have been published on the topic, and the technique has been used by countless law enforcement agencies around the globe. However, despite the popularity and extensive literature published on OP, very little is known about its evolution, current state, or findings of the field to date. Therefore, this study presents a systematic review and meta-analysis of 426 publications on OP from 1976 through 2016. Results of this systematic review suggest that there have been considerable improvements in the scientific rigor and self-assessment being conducted in the discipline, although in total, few studies have used a strong empirical approach to develop new profiles. Even fewer evaluations of the effectiveness of OP have been conducted. The first summary of offender profiles proposed for major crimes in OP literature is also presented, with results indicating some recurrent themes in profiles, but wide variations in the number, name, and description of the profiles often found. A meta-analysis of case linkage analysis research indicates that this area is statistically sophisticated, and has yielded moderate to strong accuracy rates for linking crimes to a single offender. Finally, the first analysis of the most prolific authors, researchers, departments, and outlets for OP research, and the methods, approach, and most cited publications in OP are identified. Suggestions for future research on OP and the potential impact that this may have on policy and practice are also discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
Forensic experts commonly state that many serial homicide offenders kill for the pleasure of it. At the same time, a small number of leisure scientists have suggested that serial murder may be a particular form of deviant leisure. Despite such suggestions, there has been little scholarly exploration of serial homicide from a leisure science perspective. This exploratory study adds to the existing literature by analyzing content of multiple key texts and documents that describe a large number of serial homicide cases in order to explore an understanding of murder as potential leisure. Leisure-related themes that emerged across case descriptions were (a) serial murder as a game, (b) murder for thrills and intense sensations, (c) murder for simple enjoyment and fun, and (d) murder as unique personal celebration. Subsequently, possible intrapersonal, interpersonal, and structural constraints to serial murder as possible leisure were identified. Implications for future research are also discussed.
This thoroughly updated and revised new edition provides an essential overview of a full range of psychological contributions to the understanding of crime and the processes of dealing with offenders and helping their victims. From the cognitive, developmental and social processes that influence a diverse range of crimes, including burglary, fraud, rape and murder, to the challenges faced by the police and courts in investigating crime or securing reliable testimony, the text is packed with pedagogical features that bring this fascinating subject to life. These include boxes highlighting key topics or issues around research methods, further reading and suggested essay titles. Also including chapters on rehabilitation in prisons and the psychology of victims, the text examines hot topics such as gang membership and terrorism, as well as discussing how psychology may better understand criminals and criminal behaviour in the future. It builds to a comprehensive and accessible introduction to the field. It will be ideal for students across psychology, criminology and socio-legal studies and law.
The question of 'why' and 'how' certain individuals are drawn towards behaving in a way that contravenes the 'Law of the Land' is not an easy one to address. Researchers from various different fields have nevertheless attempted to develop theoretical explanations for the existence of different types of crime and why some individuals commit such acts. Crime and Criminality draws on criminology, sociology, psychology and neuroscience to offer a balanced perspective of crime, the criminal and criminality. Coverage includes: • a comprehensive discussion of theoretical approaches to criminal behaviour, including biological, social and 'rational choice' approaches; • an analysis of legal and social definitions of crime and how these definitions influence the way specific behaviours are labelled as criminal; • an examination of different types of crime and criminals, from delinquents to 'psychopaths' and sex offenders; • an exploration of different ways in which crime is predicted, including risk assessment and offender profiling and an overview of investigative techniques. Addressing a broad range of topics and offering a synthesis of competing theoretical explanations of criminality, this book is essential reading for students taking courses in criminology, criminal psychology, criminal behaviour, forensic psychology and psychological criminology.
Purpose
– Beginning with the understanding that healthcare serial killers differ from traditional serial killers in terms of victim selection, risk and offender behavior, this paper attempts to reconceptualize how the motivations of healthcare serial killers are understood within the scope of care‐giving environments.
Design/methodology/approach
– Drawing on the current literature surrounding serial homicide and serial killers, the paper argues that healthcare serial killers, by virtue of their profession, have an advantage in committing homicides that are less likely to be detected.
Findings
– It is found that healthcare professionals work in an environment that is conducive to anti‐social behaviour like homicide. More specifically, recurring conditions within the work place (e.g. lack of a reporting system for problem employees, code of silence amongst employees) adds to the ease with which healthcare serial killers can evade capture.
Originality/value
– Research examining healthcare professionals who kill their patients is limited. The current paper provisionally adds to the current understanding of serial homicide. While offering various explanations as to why healthcare serial killers are difficult to detect, this paper also explores some potential solutions for the monitoring of healthcare professionals and protecting the vulnerable patients in their care.
The aim of this study was to investigate the effect of victim resistance in attempted homicide. The study examined 93 cases of attempted homicide. Chi-square analysis revealed that certain behaviors, such as multiple acts of violence and methods of control, are more likely to occur if the victim resists. A multivariate analysis of crime-scene actions was carried out using Smallest Space Analysis. The plot showed three clusters of variables that reflected the offender's perception of the victim as an object, vehicle, or significant person. In the first of these roles, the offender was likely to escalate the level of violence; in the vehicle role, however, the offender employed physical controls and used single acts of violence. Finally, if the victim was personally significant to the offender, the latter was more likely to use verbal control strategies and knowledge of the victim. The implications of victim resistance in light of these role functions are discussed.
A review of the literature on multiple murder reveals little systematic research on this phenomenon despite widespread media interest and figures indicating that over 3 per cent of homicide victims in England and Wales die in incidents of multiple homicide. Difficulties in both defining multiple murder and estimating its prevalance are noted, although these can be seen as essential steps towards the formulation of a comprehensive psychological model of this type of crime. A review of the literature indicates that fantasy rehearsal of murderous and sadistic acts is commonly reported in this group, and stresses the importance of examining environmental factors that could elicit and control violent behaviour. It is concluded that further research is required in three areas: (1) detection and recognition of a multiple crime perpetrator from crime scene evidence; (2) identification and recognition of risk factors within imprisoned and clinical populations; (3) identification of the treatment needs and the appropriate disposal of these offenders.
In this study, data were collected from 41 incarcerated serial rapists concerning their first, middle, and last rapes. Selection criteria required that the subjects had raped at least ten times. Collectively, the sample was found to be responsible for 837 rapes, more than 400 attempted rapes, and over 5,000 “nuisance” sexual offenses. Results showed that while the amount of force used by the rapist did not change from first to last rape overall, there were ten individuals for whom the amount of force did increase from first to last rape. Four correlates were identified that distinguished these “increasers” from “nonincreasers.” The data also indicated that when the victim resisted, the amount of pleasure experienced by the rapist was greater and the duration of the rape was longer.
The extrapolation of characteristics of criminals from information about their crimes, as an aid to police investigation, is the essence of ‘profiling'. This paper proposes that for such extrapolations to be more than educated guesses they must be based upon knowledge of (1) coherent consistencies in criminal behaviour and (2) the relationship those behavioural consistencies have to aspects of an offender available to the police in an investigation. Hypotheses concerning behavioural consistencies are drawn from the diverse literature on sexual offences and a study is described of 66 sexual assaults committed by 27 offenders against strangers. Multivariate statistical analyses of these assaults support a five-component system of rapist behaviour, reflecting modes of interaction with the victim as a sexual object. The potential this provides for an eclectic theoretical basis to offender profiling is discussed.
Despite weaknesses in the
organized/disorganized classification of serial killers, it is drawn on for "offender profiles," theories of offending, and in murder trials. This dichotomy was therefore tested by the multidimensional scaling of the co-occurrence of 39 aspects of serial killings derived 100 murders committed by 100 U.S. serial killers. Results revealed no distinct subsets of offense characteristics reflecting the dichotomy. They showed a subset of organized features typical of most serial killings. Disorganized features are much rarer and do not form a distinct type. These results have implications for testing typologies supporting expert opinion or to help understand variations in criminal acts, as well as the development of a science of investigative psychology that goes beyond offender profiling. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
To examine if serial homicide offenders are consistent across their crimes, a model was developed empirically that could be used to distinguish between crimes that were instrumental and those that were expressive. The first known three offences in each series of 69 US serial homicides committed by 23 offenders, were examined and the instrumental and expressive themes determined. Three models were then explored that test for consistency across these themes. The most liberal model was found to classify all of the offences effectively and to reveal complete consistency across the three crimes for all offenders. The implications of these results for offender profiling and further study of serial homicide are discussed. Copyright © 2005 John Wiley & Sons, Ltd.
Purpose. This paper is concerned with case linkage, a form of behavioural analysis used to identify crimes committed by the same offender, through their behavioural similarity. Whilst widely practised, relatively little has been published on the process of linking crimes. This review aims to draw together diverse published studies by outlining what the process involves, critically examining its underlying psychological assumptions and reviewing the empirical research conducted on its viability.Methods. Literature searches were completed on the electronic databases, PsychInfo and Criminal Justice Abstracts, to identify theoretical and empirical papers relating to the practice of linking crimes and to behavioural consistency.Results. The available research gives some support to the assumption of consistency in criminals' behaviour. It also suggests that in comparison with intra-individual variation in behaviour, inter-individual variation is sufficient for the offences of one offender to be distinguished from those of other offenders. Thus, the two fundamental assumptions underlying the practice of linking crimes, behavioural consistency and inter-individual variation, are supported. However, not all behaviours show the same degree of consistency, with behaviours that are less situation-dependent, and hence more offender-initiated, showing greater consistency.Conclusions. The limited research regarding linking offenders' crimes appears promising at both a theoretical and an empirical level. There is a clear need, however, for replication studies and for research with various types of crime.
In a study exploring the cross-situational consistency of behavior, 140 undergraduate Ss were video-taped in each of 3 laboratory settings, and personality descriptions of these Ss were obtained from friends and acquaintances. Analyses focused on the degree to which Ss maintained consistent patterns of behavior across laboratory settings and between these settings and daily life. The following conclusions were reached: (a) Behavior can exhibit impressive consistency at the level of psychological meaning, (b) psychological properties of situations can be detected from their behavioral effects, (c) cross-situational consistency and discriminativeness are independent, and (d) some behaviors are more consistent than others.
The authors examined the role of fantasy as an internal drive mechanism for repetitive acts of sexual violence. A sample of 25 serial sexual murderers with three or more known victims each was compared with a sample of 17 single sexual murderers, with only one known victim each. The drive mechanism was hypothesized to be an intrusive fantasy life manifested in higher prevalences of paraphilias, documented or self-reported violent fantasies, and organized crime scenes in the serial murderers. All three hypotheses were supported.
This paper uses statistical models to test directly the police practice of utilising modus operandi to link crimes to a common offender. Data from 86 solved commercial burglaries committed by 43 offenders are analysed using logistic regression analysis to identify behavioural features that reliably distinguish between linked and unlinked crime pairs. Receiver operating characteristic analysis is then used to assign each behavioural feature an overall level of predictive accuracy. The results indicate that certain features, in particular the distances between burglary locations, lead to high levels of predictive accuracy. This study therefore reveals some of the important consistencies in commercial burglary behaviour. These have theoretical value in helping to explain criminal activity. They also have practical value by providing the basis for a diagnostic tool that could be used in comparative case analysis.
Homicide grows out of a transaction between individuals. This transaction is a product of the individuals and their relationship. More may therefore be understood about different "styles" of homicide by examining how an offender acts toward a victim during the crime. The analysis of the actual behaviors used by offenders at 247 single offender-single victim homicide crime scenes indicated a pattern of frequencies that follow a continuum from where the offender reacts in an impulsive way toward the emotions engendered through the conflicted interpersonal relationship with the victim, to where the offender interacts with the victim much more at a removed level, both physically and emotionally. Behaviors can thus be seen to follow a thematic pattern that can be related to underlying psychological principles, which closely relate to how an offender interacts with the victim at the crime scene.
The aim of this study was to investigate the effect of victim resistance in attempted homicide. The study examined 93 cases of attempted homicide. Chi-square analysis revealed that certain behaviors, such as multiple acts of violence and methods of control, are more likely to occur if the victim resists. A multivariate analysis of crime-scene actions was carried out using Smallest Space Analysis. The plot showed three clusters of variables that reflected the offender's perception of the victim as an object, vehicle, or significant person. In the first of these roles, the offender was likely to escalate the level of violence; in the vehicle role, however, the offender employed physical controls and used single acts of violence. Finally, if the victim was personally significant to the offender, the latter was more likely to use verbal control strategies and knowledge of the victim. The implications of victim resistance in light of these role functions are discussed.
The study of crime scene profiling efforts elicits two important patterns of sexual murders: organized and disorganized. These law enforcement categories have been derived from evidence and patterns of evidence at the site of sexual murders. The study then explores victim information and its relationship to the two categories. In particular, we explored victim response to the offender in terms of no resistance and active resistance to the assault. We found that regardless of type of resistance, active or passive, and category of offender, death ensued. When we examined nine victims who survived, the category of offender was not the predictor, rather, “chance happenings” preserved life.
One of the main areas of concern regarding offender profiling has been the general lack of extensive empirical studies on the psychological processes underpinning this process. This study aimed to investigate the possibility of establishing a model of homicide behaviors that could be used as a basis for evaluating the scientific validity of offender profiling. A sample of 247 British single offender-single victim solved homicide cases was analyzed using a nonmetric multidimensional scaling procedure known as Smallest Space Analysis. The results indicated that homicide crime scenes could most readily be differentiated in terms of the expressive and instrumental role the victim had to the offender. The backgrounds of the offenders could similarly be differentiated by an expressive/instrumental thematic split. However, when these two elements were combined, there was a substantial mix between crime scene themes and themes of background characteristics. The results are discussed in terms of the validity of classifying homicide into a expressive/instrumental dichotomy and the implications this classification may have for offender profiling.
Generally, murder classifications have failed to be useful for investigators in identifying perpetrators of murders. Based on the experience of the authors, this article extends the definitions of four previously recognized rape-offender typologies (power-assertive, power- reassurance, anger-retaliatory, and anger-excitation) into classifications for sexually oriented killers. These types of murderers and their crime scenes are described through the dynamics of their behaviors, homicidal patterns, and suspect profiles. Each typology is followed by an actual case example that fits that particular type of killer. By identifying crime scene and behavioral factors of these killers, the homicide investigator will be more equipped to process murder scenes, prioritize leads, and apprehend killers. Unlike earlier efforts at crime scene classification, the present work addresses the behaviors, motivational continuum, and the effects of experiential learning by the perpetrators. The relative frequency of the four types within a population of murderers at the Michigan State Penitentiary is revealed.
Recent findings from person–situation studies suggest that primary control is a major factor underlying cross-situational consistency of individual behaviour. To provide evidence, we studied behaviour reflecting primary control in two modes: self-reports and observations of overt behaviour. Study I examined self-reports of 147 Ss in 15 interpersonal situations. In study II, 25 Ss were observed during role playing in five situations. The analysis focused on the degree to which Ss maintain consistent patterns of behaviour across different situations. Both studies revealed considerable degrees of consistency, thus confirming our conjecture. In the discussion attention is paid to the dispositional nature of primary control and the connections with secondary control. © 1998 John Wiley & Sons, Ltd.
Recent literature suggests that different styles of homicide will most appropriately be reflected in the different types of behaviors committed by offenders at a crime scene. These distinctions, it has been proposed (e.g., Salfati, 2000), can best be understood using an instrumental and expressive thematic framework for the way the offender acts at the crime scene. Multidimensional analysis was carried out on the crime-scene actions derived from 75 Canadian single-offender, single-victim homicides, with the aim to replicate these earlier studies. A multivariate structure resulted, encompassing both hypothesized styles. Results are discussed in terms of implications for cross-national similarities and differences in the thematic structure of homicide and explorations regarding future avenues for research regarding crime-scene classification.
The total number of serial murderers who were convicted between 1945 and 1995 in the Federal Republic of Germany (N = 61) are described in terms of their characteristics, with reference to sociodemographics, family background, social integration, intellectual capability, and personality disorders. A comparison with a larger sample of German single murderers from a previous study shows that the serial perpetrators appear to constitute a particular class of homicide offenders. In particular, the serial murderers have a higher likelihood of personality disorder, cerebral anomalies, and offense premeditation and are more likely to have had no relationship with the victim prior to the offense. With respect to differentiation among serial murderers, differences become apparent between serial murderers whose offenses have a strong sexual component (n = 22) and the remainder of the sample. Finally, the limited capacity of modus operandi and signature for linking cases in ongoing investigations is discussed.
Two decades of extensive research and intense debate have served to make clear that human behaviour is characterised by both stability and variation over time and across situations. It remains, however, to articulate a coherent theoretical account detailing the processes of person-situation interaction that give rise to this consistency and discriminativeness. Toward this end, requirements for an adequate interactional theory are reviewed. Central to the approach taken here is the assumption that because consistency and discriminativeness are properties of behaviour, these phenomena are likely to be understood only by recourse to models of behavioural production. The second section of the article then summarises a cognitive model specifying the structures and control processes comprising the behavioural output system. This model permits a reconceptualisation of individual dispositions and situational influences in terms consistent with the properties of the output system. Finally, the model is extended to the realm of nonverbal behaviour to make explicit claims concerning those conditions under which behavioural stability should be enhanced.
In a study spanning 22 years, data were collected on the aggressiveness of over 600 subjects, their parents, and their children. Subjects who were the more aggressive 8-year-olds at the beginning of the study were discovered to be the more aggressive 30-year-olds at the end of the study. The stability of aggressive behavior was shown to be very similar to the stability of intellectual competence, especially for males. Early aggressiveness was predictive of later serious antisocial behavior, including criminal behavior, spouse abuse, traffic violations, and self-reported physical aggression. Furthermore, the stability of aggression across generations within a family when measured at comparable ages was even higher than the within individual stability across ages. It is concluded that, whatever its causes, aggression can be viewed as a persistent trait that may be influenced by situational variables but possesses substantial cross-situational constancy. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Through the use of detailed examples, Shye introduces readers to the use of facet theory as a method for integrating content design with data analysis. He shows how facet theory provides a strategy for conceptualizing a study, for formulating the study's variables in terms of its purposes, for systematic sampling of the variables, and for formulating hypotheses. The book is organized into 2 parts: Part [I] introduces the reader to mapping with specific emphasis on mapping sentences, and Part [II] explores procedures for processing multivariate data. The book concludes with a discussion on the nature of scientific inquiry and the difference between a research question and observational questions.
[This book] will provide researchers with a useful technique for constructing questionnaires and for designing research instruments. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Reports findings from an exploratory study of the background characteristics of 36 male sexual murderers, their behaviors and experiences in connection with their developmental stages, and the central role of sadistic fantasy and critical cognitive structures that support the act of sexual murder. All Ss were born in the 1940s and 1950s; 33 were White, and 80% were of average to superior intelligence. A 5-phase motivational model is presented: (1) ineffective social environment, (2) formative events, (3) critical personal traits and cognitive mapping process, (4) action toward others and self, and (5) feedback filter. Clinical implications are noted. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The ‘Hollywood Effect’The Need for an Investigative PsychologySystem Integration versus Expert OpinionInvestigative PsychologyInformation RetrievalInvestigative Decision-makingAppropriate InferencesConclusions
References
Research has shown that the behaviour of people in fires and other emergencies is characterized by internally rational, socially and cognitively structured action. It has not been possible to date to discover whether the victims of fires display similar patterns of behaviour to the survivors, or act in a fundamentally different way. Following the public inquiry into the 1987 King's Cross underground fire in London, data were made available which allowed this issue to be addressed. The data mainly consisted of statements and interviews with survivors and friends of the victims. Examination of this information allowed the likely actions and intentions of 24 of the 31 victims to be pieced together with a good degree of certainty. The results showed that those who died in the fire behaved in a way similar to the survivors. Generally, victims perpetuated actions that were consistent with the normal scripts for the use of the setting, and as shaped by their place-related roles and schemata. The study shows that virtually all of the victims attempted to leave the station either by the way they had entered, or by their originally intended route. Implications of the findings for the understanding, modelling and researching of behaviour under life-threatening conditions are discussed.
Personality psychology has long recognized the importance of situations for determining behavior, but little research has directly examined the degree to which the cross-situational consistency of behavior is associated with the similarity of situations. In two studies, participants (n=138 & 116) engaged in several dyadic interactions, and their behavior was coded from a videotaped record. Behavioral consistency was examined in terms of single behaviors and person-centered behavioral profiles. Addressing subjective situational similarity, Study 1 showed that participants who rated the two situations as relatively similar were relatively consistent in their behavior across the situations. Addressing objective situational similarity, defined as the degree to which situations shared common elements, Study 2 showed that participants were more behaviorally consistent across similar pairs of situations than across dissimilar pairs. In addition, Study 2 found that behaviors that are relatively automatic and impulsive were more consistent than behaviors that are more controlled and cognitively mediated. Regardless of how situational similarity or behavioral consistency were operationalized, greater similarity was related to greater consistency.
Case linkage, the identification of crimes suspected of being committed by the same perpetrator on the basis of behavioral similarity, and offender profiling, the inference of offender characteristics from offense behaviors, are used to advise police investigations and, in relation to case linkage, have been admitted in legal proceedings. Criteria for expert evidence, such as the Daubert criteria (Daubert v. Merrell Dow Pharmaceuticals, 1993), place stringent conditions on the admissibility of expert evidence. The future contribution of these practices to legal proceedings depends, in part, on whether they are underpinned by hypotheses that are testable and supported. The 3 hypotheses of offender behavioral consistency, of offender behavioral distinctiveness, and of a homology (direct relationship) between offender characteristics and behavior were empirically examined using a sample of serial commercial robberies. Support was found for the former 2 hypotheses but not for the last. The findings of the 2 studies have implications for the future development of these practices, for legal practitioners evaluating expert evidence, and for the implementation of public policy.
Three female patrons of singles bars were murdered in separate events in Bellevue, Washington in 1990 within sixty-seven days of each other. An evaluation of those murders revealed that all the murders were linked by a distinct personal "signature" or "calling card" left by the killer. As reported in the literature, the modus operandi of a killer frequently changes from one murder to the next and is different from the killer's signature, which is a permanent psychological imprint at each scene. The murder cases reported here demonstrate an elaborate signature of one killer who engaged in a rare personalization of his necrophilic fantasies by posing, openly displaying, and sexually inserting foreign objects into each one of three victims' bodies.
A theory was proposed to reconcile paradoxical findings on the invariance of personality and the variability of behavior across situations. For this purpose, individuals were assumed to differ in (a) the accessibility of cognitive-affective mediating units (such as encodings, expectancies and beliefs, affects, and goals) and (b) the organization of relationships through which these units interact with each other and with psychological features of situations. The theory accounts for individual differences in predictable patterns of variability across situations (e.g., if A then she X, but if B then she Y), as well as for overall average levels of behavior, as essential expressions or behavioral signatures of the same underlying personality system. Situations, personality dispositions, dynamics, and structure were reconceptualized from this perspective.
In nomothetic analyses, the cross-situational consistency of individual differences in social behavior, assessed in vivo in a camp setting, dependent on the similarity in the psychological features of situations. As predicted by the social-cognitive theory of personality, idiographic analyses revealed that individuals were characterized by stable profiles of if ... then ...,situation-behavior relationships that formed "behavioral signatures" of personality (e.g., he aggresses when warned by adults but complies when threatened by peers. Thus, the intraindividual organization of behavior variation across situations was enduring but discriminatively patterned, visible as distinctive profiles of situation-behavior relationships. Implications were examined for an idiographic reconceptualization of personality coherence and its behavioral expressions in relation to the psychological ingredients of situations.
The literature on "offender profiling" suggests that different "styles" of homicide will reflect differences in the background characteristics of the offender. To test this suggestion, hypotheses were drawn from studies of aggression to propose that murder crime scenes would reveal stylistic distinctions in the role of the aggression in the offense. It was further hypothesized that these distinctions would be clearest for those crime scene indicators that reflect the instrument (cognitive) actions that shape the offense rather than the more expressive (impulsive and emotional) components. Hypotheses about associated offender characteristics were also deduced on the assumption that the murder scene theme revealed the killers' typical styles of interpersonal transaction. To test these hypotheses MDS analyses were carried out on the crime scene and offender characteristics derived from 82 single offender, single victim stranger homicides. A multivariate structure resulted, including all three hypothesized styles, allowing 65% of the cases to be assigned to unique styles and a further 36% to be assigned to appropriate hybrids. Offender characteristics related in the anticipated way to the different crime scene styles, providing a basis for law enforcement inferences about offenders in stranger murders.
Establishing behavioral consistency in serial homicide offending behavior is essential when linking homicides together and to a common offender. An examination of 35 serial homicide behaviors utilized by 90 offenders in 450 serial homicide cases was carried out to identify whether these offenders consistently performed the same behaviors across their series of homicides and whether it is more effective to examine individual behaviors or groupings of behaviors in order to identify behavioral consistency. This study provides the first empirically based evidence testing the use of using single behaviors as linking factors in linking homicide cases in a series, and shows that this method has inherent difficulties in accomplishing this, thus providing the first wave of empirical testing that questions current theories in the literature on serial homicide, which has suggested that signatures or specific key behaviors are important in understanding the consistency in an offender's behavior across the crimes. Recommendations for future studies on linking using signatures are suggested, including a more in-depth qualitative empirical evaluation of individual series.