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South African Serial Homicide: Consistency in Victim Types and Crime Scene Actions Across Series
Abstract
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.
... SHOs generally target highly vulnerable victims associated with circumstances of low social control (Egger, 1984;Horning, Salfati, & Labuschagne, 2015). Women and strangers are targeted more often, while oneoff homicide offenders most commonly target family and friends (Sturup, 2018). ...
... 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.
... If initial attempts to access the victim are unsuccessful, the offender may try again. Although it may require more time and effort to access the victim, the payoff lies in the ability to isolate them, affording more time to carry out their sexual fantasies and dispose of evidence Proulx and Beauregard 2009;Salfati et al. 2015). However, the extra time and effort involved in these tasks increase the risk of being detected or having witnesses, but successfully executing them can help in evading or delaying apprehension (Beauregard and Martineau 2013). ...
... The complexities of identifying and understanding patterns in serial offenses have been the focus of previous research (e.g. Salfati et al. 2015); however, nuances also exist in the dynamics of single-offense sexual homicides. Future research could benefit from exploring these nuances further, particularly by examining combined approach methods. ...
Victims of sexual homicide may be deceived by perpetrators who use a friendly approach to gain access to them, making it difficult for the victim to assess the danger posed by the stranger. When investigating sexual homicides committed by strangers, investigators often lack direct information, including how the perpetrator gained access to the victim. To identify potential predictors of the approach method used in sexual homicides, this study analyzed the preferences and behaviors of sexual murderers who target strangers based on their approach method. The results of the logistic regression analysis showed that in comparison to offenders using “blitz” or “surprise” attacks, those using a deceptive “con” approach tended to have more male victims, exploit vulnerability, and exhibit post‐crime organization by relocating the victim's body and successfully disposing of the weapon used in the crime. Their crimes also more frequently involved oral sex and had lower rates of victim beating. This study discusses the investigative implications of these findings.
... 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.
... Las conductas de los agresores sexuales en la escena del crimen pueden verse afectadas por factores situacionales, o de carácter contextual (Oziel, Goodwill & Beauregard, 2015;Goodwill, Lehmann, Beauregard & Andrei, 2016), pues el delito debe ser analizado al menos en dos niveles para comprenderlo: el individual y el socioambiental (Janosch & Soto, 2018). Con la denominación de factores situacionales nos referimos a elementos tales como la intensidad de la resistencia que ofrece la víctima (Salfati, Horning, Sorochinski & Labuschagne, 2015), determinadas condiciones ambientales inesperadas, el tiempo que dura la agresión, el lugar en el que se comete o bien la posible aparición de testigos y/o policías, pueden provocar un cambio en las conductas del delincuente, alterando el MO planificado (Wikström, 2006;2014). ...
... 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.
... Las conductas de los agresores sexuales en la escena del crimen pueden verse afectadas por factores situacionales, o de carácter contextual (Oziel, Goodwill & Beauregard, 2015;Goodwill, Lehmann, Beauregard & Andrei, 2016), pues el delito debe ser analizado al menos en dos niveles para comprenderlo: el individual y el socioambiental (Janosch & Soto, 2018). Con la denominación de factores situacionales nos referimos a elementos tales como la intensidad de la resistencia que ofrece la víctima (Salfati, Horning, Sorochinski & Labuschagne, 2015), determinadas condiciones ambientales inesperadas, el tiempo que dura la agresión, el lugar en el que se comete o bien la posible aparición de testigos y/o policías, pueden provocar un cambio en las conductas del delincuente, alterando el MO planificado (Wikström, 2006;2014). ...
... 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.
... 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. ...
... With the body location being the first indicator available at the onset of an investigation, this finding may have important implications for investigators. The decision of where to commit the crime and where to end it (i.e., where to leave the victim's body) is part of planning behaviors, which has previously been found to be among the most consistent features in homicide series (e.g., Salfati et al., 2015;Sorochinski & Salfati, 2010). However, findings in this study also showed that although specific crime scene indicators, such as finding the victim's body outside, strangulation, and sexual assault, may improve the investigator's ability to determine the likelihood of non-sex worker victims being part of a series that also includes sex workers, these same indicators are insufficient to confidently determine that a victim is part of a consistent sex worker-only 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.
... 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. ...
... With the body location being the first indicator available at the onset of an investigation, this finding may have important implications for investigators. The decision of where to commit the crime and where to end it (i.e., where to leave the victim's body) is part of planning behaviors, which has previously been found to be among the most consistent features in homicide series (e.g., Salfati et al., 2015;Sorochinski & Salfati, 2010). However, findings in this study also showed that although specific crime scene indicators, such as finding the victim's body outside, strangulation, and sexual assault, may improve the investigator's ability to determine the likelihood of non-sex worker victims being part of a series that also includes sex workers, these same indicators are insufficient to confidently determine that a victim is part of a consistent sex worker-only series. ...
For details of this work please see: https://www.researchgate.net/publication/331501355_Sex_Worker_Homicide_Series_Profiling_The_Crime_Scene
... Such an approach may be problematic in that it does not allow for the examination of progression of consistency and change over time. The emerging evidence suggests, however, that offenders may become less consistent as their series progress (Kearns et al. 2011;Salfati et al. 2014), highlighting the importance of fully investigating behavioural patterns across a larger number of crimes within series. ...
... 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. ...
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.
... Because of questions such as these, a recent study, aiming to provide baselines relating to the aetiology of serial homicide in South Africa, has specifically looked at detailing the nature of the victims targeted as part of these series and has shown that 48.5% of offenders target male and female victims during the course of their series and 40.6% had a mixture of single and multiple victims (Salfati, Labuschagne, Horning, Sorochinski & De Wet, 2015b). Salfati, Horning, Sorochinski, and Labuschagne (2015a) have additionally provided figures relating to consistency patterns and have illustrated that couples and live victims are not consistently targeted in South African series as a whole with couples being targeted in only 13.4% of incidents and a victim being left alive in 19.1% of incidents. Targeting of male victims is also not a common feature of South African serial homicide with men being victims in 36.4% of all incidents. ...
... It is these investigator or practitioner assumptions that have drawn the criticism of academics and researcher. In an attempt to deal with these empirical shortcomings, the studies reflected in this special issue of the Journal of Investigative Psychology and Offender Profiling (Salfati, Labuschagne, et al., 2015b;Salfati, Horning, et al., 2015a;Horning et al., 2015;Sorochinski et al., 2015) and quoted earlier were performed as a response to practice-led questions and, in turn, have provided the first generation of studies that have aimed to answer some of these questions and support or refute these assumptions, and provide a basis for a more evidenceled investigation. In turn, this has also provided a comparison between experience-informed and empirically informed literature regarding the aetiology of serial homicide in South Africa. ...
In this paper, South African serial homicide cases will be used to illustrate how practice can inform research and how research can aid practice by highlighting key questions that need to be answered and practice-based assumptions that need to be empirically tested. The cases will also be used to highlight some of the unique features of series in South Africa. Copyright © 2014 John Wiley & Sons, Ltd.
... A lack of financial resources and support has crippled most of the investigations. According to (Salfati et al., 2015) investigations in first world have been a success because of financial assistance investigators receive from the state, from management of their departments and political goodwill. According to (Muthini, 2018) criminal investors in Kenya play the role of prevention of crimes and investigation of committed crimes. ...
Latent fingerprints processing is an essential part in any criminal investigations. It is from this identification and classification of fingerprints from a surface in a crime scene that determines the success of a criminal investigation. This study focused on effect of resources on latent fingerprint processing in criminal investigations in Kenya. The objective driving this study was to examine the influence of resource orientation on criminal investigations in Kenya. The study is anchored on the Prospect Theory by Daniel Kahneman and Amos Tversky and supported by Locard's principle. This study used a cross-sectional research survey and mixed methods approach. The unit of analysis was 205 criminal investigators and analysts. A semi-structured questionnaire was used for data collection and data was analyzed using statistical methods (frequencies and percentages) and inferential statistics, and chi-square was used to test the hypothesis. The collected data was analyzed using the Statistical Package for Statistics (SPSS) version 23. The study results established that resources significantly influence criminal investigations. The outcomes of the research show the significance of availability of resources, proper training and illustrates how imperative it is for criminal investigators to have proper knowledge on crime scene identification, which all leads to effective investigations. The study recommends that the investigators should support the practice of processing mock crime scenes and surfaces for fingerprints in order to develop and refine skills in evidence collection in the face of scarcity to avoid wastage. The investigators should also leverage on technology to maximize efficiency. This might involve the use of digital tools for evidence collection and processing.
... While these studies have added important information to the literature, they do not capture the dynamic nature of serial crime in the context of the potential influence of time on behavior. Although studies that look at two crimes in a series may find higher similarity indices, studies that examine four or more crimes in a series have also found that overall consistency decreases significantly as the series progress (from 60% in the first two crimes to 25% across the first four, e.g., Salfati et al., 2015). However, few studies examine behavioral continuity in offending, and the influence that criminal behavior over the time has on the evolution of the series. ...
While the time dimension is part of the definition of serial crime, little attention has been given to understanding offending timelines and the impact of patterns of shorter or longer delays between crimes on the evolution of series on the ability to link crimes. Given the scarcity of research focusing on the timelines of serial offenders, the current study aimed to (1) determine whether series can be classified based on their timeline trajectories (e.g., progressively shorter intervals or progressively longer), and (2) determine whether these timeline trajectories correlate with trajectories of behavioral consistency and change across series. Data included 43 homicide series encompassing 216 crime scenes. Tra-jectories were determined based on whether intervals increased, decreased, or remained consistent across series, and whether timeline trajectories and behavioral trajectories align. Results revealed that distinct timeline trajectories can reliably distinguish between series. Results also suggested a complex interaction between time between crimes and how this relates to behavioral consistency and change trajectories, thus, suggesting that time is a useful, but potentially separate dimension in the linkage process.
... Both assumptions need to be met in order for crime linkage to work; i.e. the assumptions allow individual offender's crimes to be (1) linked together, and (2) distinguished from the offences committed by others. Evidence for behavioural consistency and/or distinctiveness has been found for a range of crime types including vehicle crime (Tonkin et al., 2008), burglary (Bennell & Canter, 2002;Markson et al., 2010), commercial robbery (Woodhams & Toye, 2007), sexual assault (Grubin et al., 2001), homicide (Salfati et al., 2014), and arson (Ellingwood et al., 2013;Santtila et al., 2004). There is also evidence for behavioural consistency and distinctiveness in personal robbery as evidenced in PhD work by Burrell (2012) and subsequent papers from the thesis (e.g. ...
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
... Second, while our sample is comprised of serial homicide cases from 56 countries, it was not possible to control for cultural and societal differences across countries. A growing body of research on serial murderers from countries outside of the US, however, has suggested that the behaviors of serial murderers from those countries are similar to offenders from the US (Chopin & Beauregard, 2019;Chopin & Beauregard, 2021c;Deepak & Ramdoss, 2021;Harbort & Mokros, 2001;Morton et al., 2014;Salfati, Horning, Sorochinski, & Labuschagne, 2015;Sturup, 2018;Yaksic, 2022). Also, it is still not clear how homicide cases were prioritized according to which criteria for each country in the sample. ...
... Second, while our sample is comprised of serial homicide cases from 56 countries, it was not possible to control for cultural and societal differences across countries. A growing body of research on serial murderers from countries outside of the US, however, has suggested that the behaviors of serial murderers from those countries are similar to offenders from the US (Chopin & Beauregard, 2019;Chopin & Beauregard, 2021c;Deepak & Ramdoss, 2021;Harbort & Mokros, 2001;Morton et al., 2014;Salfati, Horning, Sorochinski, & Labuschagne, 2015;Sturup, 2018;Yaksic, 2022). Also, it is still not clear how homicide cases were prioritized according to which criteria for each country in the sample. ...
Purpose
The duration of time that the serial offender remains free in the community to commit murders may be seen as a direct measure of their longevity; a sign of their success. The aim of this study is to predict the duration of the serial homicide series by examining the factors that contribute to the length of time a serial murderer is able to remain free of police detection.
Methods
Generalized estimating equations with a negative binomial link function were used to examine factors predicting the duration of series in a sample of 1258 serial murder cases.
Results
Results showed that offenders' criminal history, race (i.e., White and Hispanic), and victims of minority backgrounds significantly predicted longer duration in their murder series. A combination of multiple killing methods and atypical methods also predicted longer murder series, while the moving of the victim's body predicted shorter duration in the series.
Conclusions
This study builds upon the serial homicide literature, particularly the duration of the series. Results from this study help inform investigative efforts in serial homicide cases.
... Understanding the mindset, motivation(s), and lifestyle of the offender can help to identify important aspects of the crime(s), such as potential BDSs (Keatley 2018;Petherick and Brooks 2020). Similarly, understanding how the offender identifies with their victims (lending to levels of remorse felt by the offender) can also help to narrow down potential BDSs (Labuschagne 2006;Salfati et al. 2015). For example, the BDS of a victim where the offender felt zero remorse (i.e. ...
In homicide cases, it is difficult to provide resolution for the bereaved or to obtain a successful criminal conviction of the guilty party when no body is found. Since the mid-nineteenth century, geographic and environmental patterns have been used to better understand the relationship between crime and its environment. Now known as geographic profiling, practitioners in this field amalgamate criminological, psychological, and geographical knowledge, as well as aspects of mathematics, statistics, and physics to identify spatial patterns associated with criminal behaviour as a means of locating anchor points of an offender (where they live, or work). The same techniques can also be used to locate the covert body deposition sites of their victims. This paper aims to (1) provide a brief summary of criminal behaviour and the environment and how understanding their relationship can be helpful to geographic profiling, (2) amalgamate the available literature on the application of geographic profiling in locating clandestine graves (as most documented uses are to locate offender residences), and (3) include a geographic profile of Ivan Milat, an Australian serial killer (officially) active from 1989 to 1992, demonstrating how geographic profiling techniques can help to identify additional victims and potential body deposition sites. The information in this review will be helpful to law enforcement and practitioners to improve missing persons investigations and searches for clandestine graves.
... Understanding the mindset, motivation(s), and lifestyle of the offender can help to identify important aspects of the crime(s), such as potential BDSs (Keatley 2018;Petherick and Brooks 2020). Similarly, understanding how the offender identifies with their victims (lending to levels of remorse felt by the offender) can also help to narrow down potential BDSs (Labuschagne 2006;Salfati et al. 2015). For example, the BDS of a victim where the offender felt zero remorse (i.e. ...
In homicide cases, it is difficult to provide resolution for the bereaved or to obtain a successful criminal conviction of the guilty party when no body is found. Since the mid-nineteenth century, geographic and environmental patterns have been used to better understand the relationship between crime and its environment. Now known as geographic profiling, practitioners in this field amalgamate criminological, psychological, and geographical knowledge, as well as aspects of mathematics, statistics, and physics to identify spatial patterns associated with criminal behaviour as a means of locating anchor points of an offender (where they live, or work). The same techniques can also be used to locate the covert body deposition sites of their victims. This paper aims to (1) provide a brief summary of criminal behaviour and the environment and how understanding their relationship can be helpful to geographic profiling, (2) amalgamate the available literature on the application of geographic profiling in locating clandestine graves (as most documented uses are to locate offender residences), and (3) include a geographic profile of Ivan Milat, an Australian serial killer (officially) active from 1989 to 1992, demonstrating how geographic profiling techniques can help to identify additional victims and potential body deposition sites. The information in this review will be helpful to law enforcement and practitioners to improve missing persons investigations and searches for clandestine graves.
... Salfati's Homicide Profiling Index version 4 (HPIv4©) was used to code the data (Salfati, 2006). The results of this study were published in a special edition of the Journal of Investigative Psychology and Offender Profiling (Horning, Salfati, & Labuschagne, 2015;Salfati, Horning, Sorochinski, & Labuschagne, 2015a;Salfati, Labuschagne, et al., 2015b;Sorochinski, Salfati, & Labuschagne, 2015). ...
Scholars have explored and compared the experiences of people who use drugs (PWUDs), including encounters with the criminal justice system. However, there is a dearth of literature on police encounters with PWUDs in African countries, such as Ghana. This phenomenological study used semi-structured interviews to explore the experiences of PWUDs with the police. Thirty-eight PWUDs (mean age = 38; SD = 10.40) were purposively sampled from six drug rehabilitation centres from three regions in Ghana. Three themes were developed from the participants’ responses: police encounters, ecstasy and the psychosocial consequences of drug use, such as the psychological effects, development of criminality, disruption of people’s lifestyles and collapse of familial relationships. The topic of police encounters included the sub-themes of sudden, unannounced police sweeps, ghettos, bribery and the non-deterrence of arrests. These themes are discussed in relation to the literature, and several recommendations are proffered.
... Salfati's Homicide Profiling Index version 4 (HPIv4©) was used to code the data (Salfati, 2006). The results of this study were published in a special edition of the Journal of Investigative Psychology and Offender Profiling (Horning, Salfati, & Labuschagne, 2015;Salfati, Horning, Sorochinski, & Labuschagne, 2015a;Salfati, Labuschagne, et al., 2015b;Sorochinski, Salfati, & Labuschagne, 2015). ...
The topic of crime and violence often dominates discussions about South Africa. Excessive crime rates cause wide-reaching feelings of anxiety and fear of crime and associated violence among citizens. Research on the broad spectrum of crime and violence in South Africa has captured the imagination of many researchers internationally. Crime and violence have become part of daily life for many people living in South Africa. Commentators frequently report on the extreme prevalence of violent crime in South Africa and often label the country as one of the most violent in the world. The nature and the extent of crime and violence in the country not only influence citizens’ well-being but also have an overwhelming effect on the social structure of communities. Empirical evidence shows that the extent of violence and crime in South Africa is greater than the extent of violence and crime generally experienced globally. Why is violent crime so prevalent in South Africa? This chapter provides some insight into the violent characteristics of crime victimisation in South Africa. It provides a brief historical background of and insight into violence and crime in South Africa; describes the nature and the extent of violent crime in South Africa; explains the risk factors of crime victimisation and violence in South Africa; and illustrates South Africans’ perceptions and experiences of crime and violence. Instead of being based on theory alone, this chapter draws on the narratives of victims behind South Africa’s statistics of violent crime victimisation.
... Salfati's Homicide Profiling Index version 4 (HPIv4©) was used to code the data (Salfati, 2006). The results of this study were published in a special edition of the Journal of Investigative Psychology and Offender Profiling (Horning, Salfati, & Labuschagne, 2015;Salfati, Horning, Sorochinski, & Labuschagne, 2015a;Salfati, Labuschagne, et al., 2015b;Sorochinski, Salfati, & Labuschagne, 2015). ...
The rising population of prisoners and the movement towards compassionate care for prisoners with mental health needs highlight the need to assess correctional mental health services in the Nigerian criminal justice system. This chapter seeks to foster prisoners’ rights, and the development of feasible correctional mental health legislations. Therefore, the chapter discusses the mental health of prisoners within the Nigerian criminal justice system and provides an overview of policies, studies, and facilitators and barriers to addressing prisoner mental health in Nigeria. The chapter concludes with a discussion of practical implications.
... While these studies have added important information to the literature, they do not capture the dynamic nature of serial crime in the context of the potential influence of time on behavior. Although studies that look at two crimes in a series may find higher similarity indices, studies that examine four or more crimes in a series have also found that overall consistency decreases significantly as the series progress (from 60% in the first two crimes to 25% across the first four, e.g., Salfati et al., 2015). However, few studies examine behavioral continuity in offending, and the influence that criminal behavior over the time has on the evolution of the series. ...
Serial offenses are multiple offenses committed by the same offender with distinct time intervals in-between. While time dimension is part of the very definition of serial crime, little attention has been given to understanding the offending timelines across crime series. Understanding whether distinct patterns of increasing, decreasing, or consistent time interval patterns can be identified is an important first step in clarifying the role that the time lags between offenses play in influencing offender’s behavioral trends. Given the lack of prior research specifically focusing on the timelines of serial offenders, the current study aimed to differentiate the timeline trajectories in 43 homicide series where an offender committed at least three offenses (i.e., minimum two between crime intervals available for analysis). The focus of this study will be on the methodological and analytical challenges and steps necessary to model, identify, and differentiate timeline trajectories in serial crime.
... One of the groups of victims of particular focus in this work has been that of vulnerable victims, and subgroups of highly targeted women such as sex workers (e.g., Abrams, Palmer, & Salfati, 2016;Salfati, 2013;Salfati, Horning, Sorochinski, & Labuschagne, 2014;Salfati, James, & Ferguson, 2008;Sorochinski & Salfati, 2010). This body of work provides a further expansion of the discussion on how we should look at consistency, and includes the factor of victim targeting. ...
... Häkkänen (2008) has pointed out that most research on multiple homicides has been influenced by investigations of serial killers in the United States and that multiple-and serial-homicide offenders in Europe may differ from their American counterparts. Other scholars have also emphasised that more research from non-American settings is needed (Harbort & Mokros, 2001;Jenkins, 1988;Salfati, Horning, Sorochinski, & Labuschagne, 2015;Sturup & Lindqvist, 2014). Research has shown that offenders who kill two or more victims are different from offenders who kill only one victim (Fox & Levin, 1998;Harbort & Mokros, 2001;Kraemer, Lord, & Heilbrun, 2004;Pakkanen, Zappalà, Bosco, Berti, & Santtila, 2015;Trojan & Salfati, 2011). ...
Multiple and serial homicides constitute around 1.6% of all homicides but have unusually tragic outcomes. The aims of this study were to report the prevalence serial-homicide offences and the characteristics of serial-homicide offenders in a non-North American context. The study included all convicted serial-homicide offenders in Sweden from 1973 to 2012 (n = 25), as well as a population-based control sample of single-homicide offenders collected during 2007 and 2009 (n = 201). Similar to U.S. findings, approximately 1.6% of homicides could be attributed to serial-homicide offenders. Serial offenders were more often diagnosed with personality disorders and autism-spectrum disorders compared with single offenders; and serial offences more often involved victims who were female and unacquainted with the offender, as well as planning, sexual motives, and asphyxia as method of violence. One third of serial offences involved actions aimed at disguising the manner of death; such actions were considerably less common in single-homicide offences. Few offenders displayed the traditional profile of a serial-homicide offender; however, one third displayed sexual motives, a rate roughly 10 times higher than that in the single-homicide group. The study concludes that serial-homicide offenders should be subjected to forensic-psychiatric examinations and that research involving cross-contextual differences and similarities in serial-homicide offenders is needed.
... Specifically, this study compared the thematic differentiation of planning and violent behaviours that the offenders engage in and how this differentiation compares with that in the USA. Salfati et al. (2015a), in the fourth and final study in this special issue, looked at the key issue relating to serial homicide, notably the examination of actual patterns of behavioural consistency within series. 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, and whether there are overall and distinct patterns of consistency within serial homicide. ...
... 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 sum, thematic differentiation in planning and violence behaviours in the present South African sample, as a whole, was found to be consistent with what has previously been found in the US sample of serial homicides despite differences in the presence of some individual behaviours within the subgroups. The next step, therefore, was to examine whether each individual crime scene could be reliably classified into one dominant theme within each behavioural subgroup, prior to examining the consistency levels of the offender's use of these themes across their series (Salfati et al., 2015b). ...
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.
... This is however dealt with in another paper in the current special issue that specifically looks at the consistency of victim targeting and actions engaged in at the crime scene, across an offender's series(Salfati, Horning, Sorochinski, & Labuschagne, 2015a). ...
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.
... Also, other victim characteristics should be explored in more depth. The results from this study suggest that there is a very real need to go beyond looking at victim characteristics on their own, to looking at them within the larger context of the offense, by looking at the actions of the offenders against specific victim groups (see Salfati, Horning, Sorochinski, & Labuschagne, 2015). ...
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.
... Specifically, this study compared the thematic differentiation of planning and violent behaviours that the offenders engage in and how this differentiation compares with that in the USA. Salfati et al. (2015a), in the fourth and final study in this special issue, looked at the key issue relating to serial homicide, notably the examination of actual patterns of behavioural consistency within series. 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, and whether there are overall and distinct patterns of consistency within serial homicide. ...
This study presents the criminal profile of homicide offenders in prisons across Brazil. The sample was N = 189 male participants, single-victim homicide (n = 87) and serial homicides (n = 102). Most of the sample had less than nine years of formal education and the most frequent age was 15–28. Robbery homicide was the most frequent motivation for both groups and fight/settling scores were more common in the single homicide group. Men victims were more frequent for both groups. Acquaintances (56.3%) in single homicides and unknown to the aggressor (64.4%) in serial homicides. Firearms was the main method of execution. Mental disorder was more frequent (24.5%) in serial homicides.
South Africa has recorded a high number of serial murders in its modern history. Since the mid-1990s, over 170 murder series have been identified by the South African Police Service (SAPS). This led to the SAPS creating a specialised unit to deal with this and related crimes in the mid-1990s, fashioned along the lines of the FBI’s Behavioral Analysis Units. This chapter sets the historical context of serial murder in South Africa and reviews the existing research on South African serial murder including the landmark 2015 research conducted in conjunction with the John Jay College of Criminal Justice, and is one of the largest serial murder studies using police case files in the world to date. Insights into how the SAPS adapted to investigate these cases are also provided. Case studies are used to bring the local nuances of South African cases to life.
Previous studies of homicides in South Africa have examined serial murders and mass killings. While some scholars have examined parricides in African countries such as Ghana and Zimbabwe, few have examined the intersection of parricide and multiple victim homicides in the context of South Africa. This paper examines multiple victim parricides in a South African context using newspapers and court records as data. Eighteen cases of multiple‐victim parricides were identified and analysed. Our findings indicate that multiple victim parricides in South Africa are shaped by residential patterns as well as social and cultural factors that are unique to South Africa that are embodied in the offence characteristics. The implications on the findings are discussed.
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.
Existing inquiries purporting to study and describe offender behaviour in stranger child abduction (SCA) have utilised an overly narrow definition of modus operandi (MO), focusing only on very outset of the offence. The study aims to reflect changes that occur as the offence proceeds and to examine whether differentiating between attempted and completed cases can provide greater understanding of MO in SCA. The MO utilised by offenders in 78 cases of SCA retrieved from publicly available U.K. sources were examined. Descriptive analysis was used to determine which types of behaviour were present. Multidimensional scaling was used to categorise these behaviours and to establish whether any relationships existed between them, with view to ascertaining whether there were any clear patterns among strategies. Results found support for differentiating attempted and completed offences, with the analysis highlighting that offenders who utilised multiple means of control, who were more aggressive, and who shifted their MO from one theme to another, were more likely to complete the offence. The study concludes that more nuanced categorisations of SCA offending approaches, which reflect change over time, are required, and argues for additional, contextual information to be incorporated into future work.
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).
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
Considerable evidence has amassed in studies of both nonoffender and offender samples that demonstrates both that sexual aggression is determined by a multiplicity of variables and that convicted sexual offenders are markedly heterogeneous (Knight, Rosenberg, & Schneider, 1985; Malamuth, 1986). Attempts both to identify sexually coercive men in normal samples and to assess etiology, concurrent adaptation, treatment efficacy, and recidivism for convicted sexually aggressive offenders have also suggested that the critical determining components of sexual aggression interact in complex ways. The purpose of this article is to survey both the offender and nonoffender sexual aggression research for evidence about which dimensions should be included in multivariate models that attempt to discriminate rapists from nonrapists, to identify subgroups among rapists, or to enhance the efficiency of dispositional decisions about these offenders.
Serial rape attracts much media attention and has become a topic of increased interest and concern. However, both locally and internationally, there is a paucity of empirically based research. The limited research which exists often does not focus on the victim as a “subject” which could contribute to solving existing cases or in curtailing the serial rapist. In this article, socio-demographic characteristics of 75 victims of serial rape, and how they were selected by the rapist were used to construct a general profile of the people who are the
targets of the serial rapist. Factors or contexts which put women at risk are also identified and investigated. Comparisons are made between the characteristics of the victims of serial rapists in other countries, while comparisons are also made between the victims of single victim rapists and those of the serial rapist. Of great concern is, amongst others, that the results indicate that in South Africa a large number of victims of the serial rapist are girl children. Limitations of the research are indicated, while a suggestion for future research concludes the article.
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.
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.
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.
Although distinct offence action patterns have been identified for different forms of sexual and violent crime, a generic psychological framework for this differentiation has yet to be advanced. An innovative framework derived from the emerging criminal narrative approach provides a significant contribution to the differentiation of offending styles. Canter (1994) argues that offenders’ empathy deficit leads them to assign a Victim, Object or Person role to their victims within their personal narratives. The evidence for this model is examined across 33 offence actions in 66 stranger rapes, 24 offence actions in 50 stalking offences and 39 offence actions in 50 serial murder offences. Hypothesised offence actions reflecting the Roles are found in distinct regions of Smallest Space Analysis (SSA-I) configurations for all three offence types. This evidence across diverse offence forms leads to the suggestion that the Roles assigned to victims within offenders’ narratives provide a generic framework for differentiating offending styles in all interpersonal crimes. The different Victim Roles articulate qualitatively different variants of the established control and empathy deficit components in sexual and violent offending, contributing to the debate about the operation of these components and having significant treatment implications.
Secondary data analyses on two analogous data sets assessed the ability of crime-scene variables observed in serial rapes to predict classification in the Massachusetts Treatment Center, Rapist Typology Version 3 (MTC:R3). Data sets from the FBI containing extensive coding of crime-scene information but minimal offender data were analyzed to select optimal predictors by examining the frequencies and both within-crime and across-crime consistencies of crime-scene indicators. Analogous predictors were identified in the MTC database, which contains extensive offender data but minimal crime-scene data, and these indicators were employed to predict rapist type. Promising predictive results emerged in the domains of adult antisocial and expressive aggression. In addition, the domains of sadism, offense planning, and relation with victim showed high internal consistency and good to high cross-crime consistency, suggesting that predictive scales are possible for these domains.
The present study aimed to identify dimensions of variation in serial homicide and to use these dimensions to behaviourally link offences committed by the same offender with each other. The sample consisted of 116 Italian homicides committed by 23 individual offenders. Each offender had committed at least two homicides. As some offenders had worked together and some murders involved more than one victim, there were 155 unique pairings of offenders and victims. Dichotomous variables reflecting crime features and victim characteristics were coded for each case. Using Mokken scaling, a nonparametric alternative to factor analysis, seven dimensions of variation were identified. Five of the dimensions described variations in the motivation for the killings. Three of these were concerned with aspects of instrumental motivation whereas two of the motivational scales described variations in sexual motivation. The two remaining dimensions dealt with the level of planning evident in the crime scene behaviour of the offender. Two dimensions were identified: one consisting of behaviours suggesting a higher level of control and another describing impulsiveness. Using discriminant function analysis with the dimensions as independent variables and the series an offence belonged to as dependent variable, 62.9% of the cases could be correctly assigned to the right series (chance expectation was 6.2%). The implications of the results for serial homicide investigations are discussed.
one of the major goals of our research program at the Massachusetts Treatment Center during the 1980s has been addressing these critical taxonomic problems by systematically applying this approach to the study of sexual offenders / it is the intent of this chapter to give an overview of this programmatic approach and to summarize some of the taxonomic structures that have emerged from our research (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Describes a method for analyzing criminal behavior patterns by using computerized statistical cluster analysis. Illustrations are derived from burglary methods of operation. Analysis techniques can be applied to daily incidence reports with 4 anticipated advantages. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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.
Personality psychologists have suggested that the context of a behaviour should be considered in studying behavioural consistency. They have operationalised this as studying ‘if (situation)–then (behaviour)’ contingencies and have demonstrated an association between situational similarity and behavioural consistency. Previous research of behavioural consistency in the forensic setting has tended to focus exclusively on the ‘then (behaviour)’ part of the contingency—the offender's behaviour. This paper considers methodological approaches that might be used to investigate whether situational similarity is associated with behavioural consistency, and to develop if–then contingencies. Seventy-eight offences by stranger sex offenders were subjected to constant comparison framework analysis to develop an offender behaviour checklist and a victim behaviour checklist, and a combination of constant comparison framework analysis and hierarchical cluster analysis were used to develop victim behavioural themes. Consistency in offender behaviour and similarity in victim behavioural themes (representing situational similarity) were measured using Jaccard's coefficient for offence pairs within 13 solved series of stranger sexual assaults. Correlational analyses were used to assess the relationship between situational similarity and behavioural consistency. Contrary to expectations, no relationship was found. The utility of linguistic computational programs in creating if(victim behaviour)–then(offender behaviour) contingencies was tested with encouraging results. However, little evidence of consistency in if(victim behaviour)–then(offender behaviour) contingencies was found within the offence series. Explanations are proposed for these novel findings and avenues for future research are suggested. Copyright © 2008 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.
The purpose of this study is to determine if readily available information about commercial and residential serial burglaries, in the form of the offender's modus operandi, provides a statistically significant basis for accurately linking crimes committed by the same offender. Logistic regression analysis is applied to examine the degree to which various linking features can be used to discriminate between linked and unlinked burglaries. Receiver operating characteristic (ROC) analysis is then performed to calibrate the validity of these features and to identify optimal decision thresholds for linking purposes. Contrary to crime scene behaviours traditionally examined to link serial burglaries, the distance between crime site locations demonstrated significantly greater effectiveness as a linking feature for both commercial and residential burglaries. Specifically, shorter distances between crimes signalled an increased likelihood that burglaries were linked. Thus, these results indicate that, if one examines suitable behavioural domains, high levels of stability and distinctiveness exist in the actions of serial burglars, and these actions can be used to accurately link crimes committed by the same offender. Copyright © 2005 John Wiley & Sons, Ltd.
Case linkage involves identifying crime series on the basis of behavioral similarity and distinctiveness. Research regarding
the behavioral consistency of serial rapists has accumulated; however, it has its limitations. One of these limitations is
that convicted or solved crime series are exclusively sampled whereas, in practice, case linkage is applied to unsolved crimes.
Further, concerns have been raised that previous studies might have reported inflated estimates of case linkage effectiveness
due to sampling series that were first identified based on similar modus operandi (MO), thereby overestimating the degree
of consistency and distinctiveness that would exist in naturalistic settings. We present the first study to overcome these
limitations; we tested the assumptions of case linkage with a sample containing 1) offenses that remain unsolved, and 2) crime
series that were first identified as possible series through DNA matches, rather than similar MO. Twenty-two series consisting
of 119 rapes from South Africa were used to create a dataset of 7021 crime pairs. Comparisons of crime pairs that were linked
using MO vs. DNA revealed significant, but small differences in behavioral similarity with MO-linked crimes being characterized
by greater similarity. When combining these two types of crimes together, linked pairs (those committed by the same serial
offender) were significantly more similar in MO behavior than unlinked pairs (those committed by two different offenders)
and could be differentiated from them. These findings support the underlying assumptions of case linkage. Additional factors
thought to impact on linkage accuracy were also investigated.
KeywordsComparative case analysis–Linkage analysis–Behavioral linking–Sexual assault–Sexual offense
The present study investigated the possibility of statistically linking arson cases based on consistency of behaviors from one crime scene to another. Serial and spree arson cases were studied to differentiate underlying themes and to link cases committed by the same offender. The material consisted of 248 arson cases which formed 42 series of arsons. A content analysis using 45 dichotomous variables was carried out and principal components (PCA) analysis was performed to identify underlying themes. Summary scores reflecting the themes were calculated. Linking effectiveness was tested with a discriminant analysis using the summary scores. The PCA analysis was successful and underlying themes which were in accordance with previous studies could be identified. Six factors were retained, in the PCA. The linking of the arson cases was possible to a satisfactory level: 33% of the cases could be correctly linked and for over 50% of the cases, the series they actually belonged to was among the ten series identified as most probable on the basis of the linking analysis. From a practical point of view, the results could be used as a basis for developing support systems for police investigations of arson. © Copyright Springer, 2004
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.
Considerable evidence has amassed in studies of both nonoffender and offender samples that demonstrates both that sexual aggression is determined by a multiplicity of variables and that convicted sexual offenders are markedly heterogeneous (Knight, Rosenberg, & Schneider, 1985; Malamuth, 1986). Attempts both to identify sexually coercive men in normal samples and to assess etiology, concurrent adaptation, treatment efficacy, and recidivism for convicted sexually aggressive offenders have also suggested that the critical determining components of sexual aggression interact in complex ways. The purpose of this article is to survey both the offender and nonoffender sexual aggression research for evidence about which dimensions should be included in multivariate models that attempt to discriminate rapists from nonrapists, to identify subgroups among rapists, or to enhance the efficiency of dispositional decisions about these offenders.
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.
In this study, the relationship between psychopathy and the prepetration of sexual homicide was investigated. The official file descriptions of sexual homicides committed by 18 psychopathic and 20 nonpsychopathic Canadian offenders were coded (by coders unaware of Psychopathy Checklist--Revised [PCL--R] scores) for characteristics of the victim, victim/perpetrator relationship, and evidence of gratuitous and sadistic violent behavior. Results indicated that most (84.7%) of the sexual murderers scored in the moderate to high range on the PCL--R. The majority of victims (66.67%) were female strangers, with no apparent influence of psychopathy on victim choice. Homicides committed by psychopathic offenders (using a PCL--R cut-off of 30) contained a significantly higher level of both gratuitous and sadistic violence than nonpsychopathic offenders. Most (82.4%) of the psychopaths exhibited some degree of sadistic behavior in their homicides compared to 52.6% of the nonpsychopaths. Implications for homicide investigations are discussed.
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.
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.
Aimed at critically examining how offenders and offences are conceptualised, Investigative Psychology has seen a substantial increase in studies of crime scene behaviours and offender characteristics using multidimensional scaling (MDS) analyses that build thematic models of crime scene behaviours based on the co-occurrence variables and then testing the frameworks by determining if cases are dominant in a single thematic region. Although methods have been developed, issues that arise from using different methods and the effect on the results obtained have never been thoroughly discussed. Framed in the context of the evolution of how people have been classified in offender profiling research and elsewhere, this paper examines the established procedures used in MDS studies to determine dominance. Two methods—proportional versus the quantity of variables present—are compared across four levels of stringency within a framework of homicide offenders' criminal convictions. Results support the most common criterion used in prior studies of homicide and demonstrate that the subject of the framework or type of variables may dictate which method is more appropriate. The results strengthen the argument that a standard protocol for determining dominance should be adopted to increase consistency across studies to add to the development of Investigative Psychology. Copyright © 2009 John Wiley & Sons, Ltd.
A sample of serial stranger rape cases ( n = 43) that had occurred in Finland during the years 1983–2001 were studied with the objectives being to: (a) describe the characteristics of the offenders; (b) explore the structure of serial rape; and (c) demonstrate behavioural linkage through an analysis of the offenders' crime scene behaviour using both multidimensional scaling (MDS) and discriminant function analysis (DFA). The material was content analysed with regard to the occurrence of a number of dichotomous variables. The inter-relationships of the variables was studied using MDS. The analysis revealed two previously identified major modes of interaction with the victim: involvement and hostility. Employing MDS and DFA, it was shown that the offences of different offenders were distinguishable in terms of variation between the offences of different offenders and consistency within the offences of a single offender. Using DFA, the classification accuracy clearly exceeds that expected by chance, and 25.6% of the cases were classified without any error. The results are discussed in relation to their practical utility and previous studies. Copyright © 2005 John Wiley & Sons, Ltd.
The ‘Hollywood Effect’The Need for an Investigative PsychologySystem Integration versus Expert OpinionInvestigative PsychologyInformation RetrievalInvestigative Decision-makingAppropriate InferencesConclusions
References
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.
This article presents a view of planning as a task supported by a dynamic memory. This view attempts to ingegrate models of memory, learning, and planning into a single system that learns about planning by creating new plans and analyzing how they interact with the world. We call this view of planning case‐based planning.
A case‐based planner makes use of its own past experience in developing new plans. It relies on its memory of observed effects, rather than a set of causal rules, to create and modify new plans. Memories of past successes are accessed and modified to create new plans. Memories of past failures are used to warn the planner of impending problems, and memories of past repairs are called upon to tell the planner how to deal with them.
This view of planning from experience supports and is supported by a learning system that incorporates new experiences into the planner's episodic memory. This learning algorithm gains from the planner's failures as well as its successes. Successful plans are stored in memory, indexed by the goals they satisfy and the problems they avoid. Failures are also stored and indexed by the features in the world that predict them. By storing failures as well as successes, the planner is able to anticipate and avoid future plan failures.
Case‐based planning is aimed at improving planning behavior in three areas: failure avoidance, plan repair, and plan reuse. It also attempts gains over current learning systems, in that the learning is driven by the functional needs of a planner.
This paper examines the research on serial murder and its relationship to antisocial personality disorder and sexual sadism. The concept of malignant narcissism is also discussed. Case studies of serial killers are examined regarding the nature of sexual violation and crime scene behavior.
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.
The violent criminals defined in this article are a small, exceptionally dangerous group of offenders designated by the authors as "lethal predators." They have a history of sexual predation, have killed at least once, and are mentally abnormal but legally sane. They are highly likely to keep killing as long as they are free. Laws permitting civil commitment of dangerous and mentally abnormal sexual predators after they have completed criminal prison sentences have been upheld by the U.S. Supreme Court. Such laws can provide a legal means of keeping these highly dangerous killers confined so they cannot kill again.
Sexual violence is a multidimensional concept that is not completely understood even within forensic psychiatry. Violent sexual behaviour such as sexually sadistic homicides would be included within the definition, but it is commonly defined more broadly as any deviant sexual behaviour. In this review, the broadest definition of sexual violence is used in order to facilitate the most comprehensive review of scientific articles in the field.
This review covers sexual violence from the extreme of sexually motivated homicides to sexual violence in Internet crimes. The review can be divided into four subject areas. The first relates to extreme sexual violence such as sexually motivated homicide, the second area refers to Internet sexual offending, the third relates to studies on the characteristics of the perpetrators of sexual offending behaviour and the fourth relates to risk evaluation and the prevalence of sexual violence.
Significant advances have been made in relation to sexual sadism. Deviant sexual behaviour using the Internet is being studied. Significant research advances continue in understanding clinical characteristics of various types of sexual offenders. Other important areas of research relate to meta-analytical studies of sexual offenders.
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.
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