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Linking serious sexual assault through behaviour
... The past 15-20 years have seen case linkage research and practice flourish, with support for linkage practice found across high-volume offences, as well as interpersonal offences (Bennell et al., 2010(Bennell et al., , 2014Burrell and Bull, 2011;Grubin et al., 2001;Labuschagne, 2006;Santtila et al., 2008;Slater et al., 2015;Tonkin and Woodhams, 2017;Tonkin et al., 2011Tonkin et al., , 2012Winter et al., 2013;Woodhams et al., 2007bWoodhams et al., , 2019Woodhams and Labuschagne, 2012;Woodhams and Toye, 2007). As research and investigative methods continue to develop, specialised databases have been created to assist in the case linkage process, such as the Canadian Violent Crime Linkage Analysis System (ViCLAS), the Violent Criminal Apprehension Program of the United States of America (USA) and Australia's Violent and Sexual Crimes Database (VSCD). ...
... Accurate case linkage can benefit investigations and trials. During investigations, the identification of linked offences can reduce the case-load of police departments and investigators by directing resource allocation, facilitating collaboration between jurisdictions and narrowing down suspect pools (Bartol and Bartol, 2013;Burrell and Bull, 2011;Grubin et al., 2001;Santtila et al., 2008;Woodhams, et al., 2007a). Case linkage can also exclude cases that may not be part of a series or link cold cases to current cases to increase closure rates (Petherick and Ferguson, 2015). ...
... In court, the results of case linkage can be used to attribute multiple cases to an offender, provide additional evidence against a perpetrator and influence sentencing determinations (Burrell and Bull, 2011;Turvey, 2008). Conversely, incorrect case linkage can have detrimental effects, such as wasting time and resources, misled policing and wrongful convictions (Grubin et al., 2001;Winter et al., 2013). ...
Purpose
Case linkage theory and practice have received growing empirical support; however, they have yet to be examined fully within Australia. For sexual assault case linkage to be successful, it is assumed that a serial rapist will behave relatively consistently across offences yet distinctively compared to other offenders. The purpose of this paper is to test the underlying principles of case linkage, behavioural consistency and distinctiveness, as well as distinguishing accuracy.
Design/methodology/approach
In total, 250 solved stranger rapes by 171 offenders (46 serial rapists, 125 one-off rapists) were taken from Queensland Police Service (QPS) crime records. All possible crime pairings were created and cross-crime similarity was assessed using Jaccard’s coefficient. Receiver operating characteristics (ROC) analysis was used to examine the ability to distinguish between linked and unlinked offence pairs.
Findings
Serial linked pairs had the highest Jaccard’s coefficient (0.456), followed by non-serial unlinked (0.253) and finally, serial unlinked pairs (0.247). Within the ROC analysis, an area under the curve value was found of 0.913, indicating excellent distinguishing accuracy. Both the underlying principles of behavioural consistency and distinctiveness were supported through theoretical and practical methods. This paper provides the first analysis of serial rape case linkage in Australia, adding validity to this practice.
Research limitations/implications
The authors wish to acknowledge the support and assistance from the QPS in undertaking this research. The views expressed in this publication are not necessarily those of the QPS and any errors of omission or commission are the responsibility of the authors.
Practical implications
This paper provides validity to the practice of case linkage using a database within Australia. The results of this paper can be used to inform investigators of serial offender behaviours. The theories of offender consistency and distinctiveness are supported, highlighting the importance of behavioural evidence for practitioners. This paper provided a practical increase of the quantity and quality of offences uploaded on the Australian violent and sexual crimes database, which will assist further linkage efforts.
Originality/value
This paper is the first in Australia to examine consistency, distinctiveness and case linkage of serial stranger rape. Thus is contributes significantly not only to an increased understanding of serial rape and case linkage in Australia but also brings Australia closer to modern research practices in this field.
... In some countries, it is also used to support prosecutions in court (Labuschagne, 2006(Labuschagne, , 2012Pakkanen, Santtila, & Bosco, 2014). Using offender behaviour to link crimes can be advantageous where more traditional linkage methods are expensive and time-consuming (Pakkanen, Zappalà, Grönroos, & Santtila, 2012), or where there is limited or no physical forensic evidence (Grubin, Kelly, & Brunsdon, 2001;Labuschagne, 2014). ...
... For example, in studies of the principles underpinning crime linkage (rather than its practice), geographical and temporal information results in statistical predictions of linkage that are more accurate (Tonkin, Woodhams, Bull, Bond, & Palmer, 2011), as have behaviours over which offenders are thought to be able to exercise greater control and which are less susceptible to situational influence (Grubin et al., 2001). ...
... This consideration is especially important given that crime linkage is used in this capacity across many different policing contexts and across different continents, including countries in Europe (Rainbow, 2014), North America (Hazelwood & Warren, 2004), and Africa (Labuschagne, 2006). Inaccurate linkage predictions may hinder, rather than help, an investigation, including the inappropriate allocation of law enforcement resources and, in the case of incorrectly identifying several cases as linked, generating unwarranted media interest and unnecessary public anxiety (Grubin et al., 2001). With these considerations in mind, academic research needs to focus, not just on the theoretical underpinnings of crime linkage but also on the practice of crime linkage itself. ...
Crime linkage has been the subject of increasing attention in academic research. Research has found support for the principles of behavioural consistency and distinctiveness, which underpin crime linkage, but this does not provide direct evidence as to whether crime linkage is useful in practice. This literature review draws together documentation that refers to the practice of crime linkage, from assessing analysts' efficacy, to discussing the usage of computerised tools to assist with the linkage process, to providing a comprehensive outline of the process itself. The implications of the amount and type of information currently available are discussed, including the variations in practice and terminology that were explored. Avenues for future investigation and the manner in which future research could be conducted are set out in a research agenda.
... Although some variation has been found in the type and level of behavioral consistency shown by different types of offenders, and when using different analytical methods, research on CLA has been fairly successful in identifying solved and unsolved cases committed by the same offender. Specifically, behavioral consistency of serial offenders has been successfully conducted for burglary (e.g., Bennell & Canter, 2002;Bennell & Jones, 2005;Goodwill & Alison, 2006;Green, Booth, & Biderman, 1976;Yokota & Canter, 2004), arson (e.g., Santtila, Fritzon, & Tamelander, 2005), sexual assault (e.g., Canter et al., 1991;Deslauriers-Varin & Beauregard, 2013;Grubin, Kelly, & Ayis, 1997;Grubin, Kelly, & Brunsdon, 2001;Knight, Warren, Reboussin, & Soley, 1998), robbery (e.g., Woodhams & Toye, 2007), and homicide (e.g., Melnyk, Bennell, Gauthier, & Gauthier, 2011;Salfati & Bateman, 2005). Within these offense types, the most consistent offending behaviors have been the distance an offender traveled to the crime, the time interval between offenses, and a combination of related behaviors committed at the crime scene, known as the modus operandi or offense style 1 (e.g., Markson, Woodhams, & Bond, 2010;Tonkin, Woodhams, Bull, Bond, & Palmer, 2011). ...
... Among the most relevant findings for CLA from DLC research is the fact that offenders tend not to specialize in certain offense types, such as property crimes or violence, in their criminal careers, but there is "a small but significant degree of specialize in the midst of a great deal of versatility" (Piquero, Farrington, & Blumstein, 2003, p. 454). In fact, DLC studies have shown that offenders increase their criminal versatility as their careers lengthen, so chronic offenders commit the widest variety of crime types (Farrington & West, 1993;Grubin et al., 2001;Moffitt, Caspi, Harrington, & Milne, 2002;Sullivan, McGloin, Ray, & Caudy, 2009). Other research suggests that offenders are more versatile at the start of their career, and then specialize in crime types that are better suited to their more refined tastes and skills so they become more "successful" offenders (see, for example, Blumstein, Cohen, & Farrington, 1988;DeLisi et al., 2011;Francis, Soothill, & Fligelstone, 2004;Mcgloin, Sullivan, & Piquero, 2009;Sullivan, Mcgloin, Pratt, & Piquero, 2006). ...
... Davies, Tonkin, Bull, & Bond, 2012;Grubin et al., 1997). It also means that analyzing a multivariate profile of offending behaviors, rather than each individual crime scene behavior, is the most promising method of determining specialization in crime scene behaviors across multiple offenses (Burrell, Bull, & Bond, 2012;Grubin et al., 2001;Markson et al., 2010;Santtila et al., 2005;Santtila, Runtti, & Mokros, 2004;Woodhams, Grant, & Price, 2007). ...
This study evaluates the behavioral consistency in offending styles among a sample of serial burglars from the United States. Three popular specialization analyses—Jaccard’s coefficient, the forward specialization coefficient (FSC), and the Diversity (D) index—are used to compare if, and how much, variation exists in the behavior of serial burglars committing different styles of offenses, among the three analyses. Results show that there is variation across the analyses, with the FSC and D index suggesting serial burglars are relatively consistent in their burglary offense styles. However, burglars with organized and disorganized offense styles are more consistent in behavior across offenses than burglars who committed opportunistic and interpersonal style offenses. These findings have important methodological implications for criminological research, and practical implications for policing and crime linkage analysis.
... These different terms refer to a form of behavioural analysis, based on the behavioural similarity and distinctiveness of the offence, which is used to identify a series of crimes committed by the same offender , often when there is a lack of physical evidence (e.g., DNA) to identify the offender (Davies, 1991). Their research supports the assumption that offenders behave consistently within crime types, including sexual assault (e.g., Grubin, Kelly, & Brunsdon, 2001;Knight, Warren, Reboussin, & Soley, 1998), homicide (e.g., Salfati & Bateman, 2005;, burglary (e.g., Bennell & Canter, 2002;Bennell & Jones, 2005;Goodwill & Alison, 2007;Green et al., 1976), robbery (e.g., Woodhams & Toye, 2007), and arson (e.g., Fritzon, Canter, & Wilton, 2001;Santtila, Fritzon, & Tamelander, 2005). ...
... The main similarity is that both share the underlying assumption of offender behavioural consistency; the hypothesis that offenders will display in their behaviour consistency across a series of offences (Canter, 1995b;. The possibility of linking a series of crimes can be beneficial and helpful for the police as it allows for the collection of information across different crimes, the potential of increasing evidence against an offender, the combining of separate investigations utilising more effective police resources and lastly, the production of similar fact evidence in legal proceedings (Grubin et al., 2001;Hazelwood & Warren, 2003;Labuschagne, 2006). There is growing potential for the utility of linkage analysis in investigating less serious crimes (e.g., robbery), beyond its current success with investigating stranger rape or murder, or other more serious crimes . ...
... While, studies have shown behavioural consistency of offenders across crimes for different crime types (e.g., Bennell & Jones, 2005;Grubin, Kelly, & Brunsdon, 2001;, there has been little conclusive support for the assumption of homology. A few studies have examined the relationship between background characteristics and offence behaviour and to some extent, support the homology assumption in that bivariate relationships have been found (Canter & Fritzon, 1998;Davies, Wittebrood, & Jackson, 1998;House, 1997). ...
The area of Offender Profiling generates a lot of interest in both the academic field and the everyday world as a result of a few highly prolific cases (e.g., Jack the Ripper, Boston Strangler). Historically, profiling has been based on intuition and experience, but as the field has matured, the need to be more scientific in approach has led to the development of empirically driven models/typologies of offender behaviour based.Different approaches have attempted to define, and operationalize offender profiling based on the individual principles inherent in each approach.Briefly, the Criminal Investigative approach to profiling initially relied upon the investigative experience and observation of FBI agents who soon started publishing on the topic. However, in more recent years, large databases containing information on serial and violent crime/criminals has allowed for more empirical approaches to emerge (Snook, Luther, House, Bennell, & Taylor, 2012). The Clinical approach, on the other hand, adopts a model of offender profiling that centers on the concept of motives. Finally, and most recently, the Statistical approach has aimed to provide a testable scientific framework for identifying and inferring offender characteristics/motives.However, none of these approaches alone can explain the complexities of offending behaviour. The Criminal Investigative approach brings with it a multitude of experience from investigators; the Clinical brings an abundance of medical and privileged clientbased knowled ≥ while the Statistical approach aims to provide more objective measures and examination of offending behaviour. Without the experience, knowledge, and information offered by the first two approaches, the ability to know which variables to look for or code for would be lost. However, the latter Statistical approach allows practitioner-based knowledge to be integrated with the objective examination of offending patterns and correlated findings. Therefore, the way forward should seek to integrate all of the approaches (Alison, West, & Goodwill, 2004; Alison, Goodwill, Almond, van den Heuvel, & Winter, 2010). Together, the approaches strengthen each other and give weight and support to one another. More importantly, they help strengthen the field of offender profiling as a whole.In this chapter, an overview and critique of the offender profiling literature; its underlying assumptions; and the relationship between the crime scene actions and the offender characteristics will be presented. In addition, each of the approaches to offender profiling that have developed over its short empirical history will be described and critiqued.
... Much of the research interest in whether offenders are consistent in their offending behavior has focused on the more serious types of crime, such as sexual assault (1,192021) and murder (22). However, studies have also been conducted for arson (23), commercial and residential burglaries (5,15,24), and commercial robbery (25). ...
... Other studies have identified for each crime in their sample the 10 most similar crimes. They have then assessed whether any of the crimes in this selection were in fact committed by the same offender (1,21,23). All such studies have confirmed that it is possible to link crimes and have therefore supported the two assumptions of behavioral consistency and inter-perpetrator behavioral variation. ...
... Three studies have suggested that offenders are consistent and distinctive enough for linked and unlinked crimes to be accurately differentiated (5,15,25). Furthermore, five studies have demonstrated that crimes can be associated with other crimes in their series, which would require both offender consistency and distinctiveness (1,19,21,23,24). Such research has ecological validity; therefore its findings should be relevant to practice. ...
This chapter begins by explaining the purposes of linking crimes committed by the same offender and what case linkage can add to a police investigation and prosecution. The various steps involved in the process of case linkage are explained. The assumptions of behavioral consistency and inter-individual behavioral variation, which case linkage rests on, are outlined, and the research that has begun to test these assumptions is reported. The effect of poor-quality data on the case linkage process and on empirical research is examined. Current methods and future developments for overcoming this difficulty are described. The obstacles to identifying linked crimes across police boundaries are discussed. Case linkage research and practice are compared with various criteria for expert evidence with promising results. The chapter closes by considering future avenues for research and practice in case linkage.
... Identifying serial crimes and linking these offences to individual offenders is a crucialto streamline investigative efficiency (Santtila, Junkkila, & Sandnabba, 2005), pool evidence (Bennell et al., 2009 ) and/or narrow the search for the offender (eg, through geographic profiling and/or offender profiling (Canter & Larkin, 1993; Santtila et al., 2004; Santtila, Häkkänen, & Fritzon, 2003)). Linking offences can be relatively straightforward if forensic evidence is found at the crime scene (Grubin, Kelly, & Brunsdon, 2001). However, forensic evidence is not always present; for example, Ewart, Oatley, and Burn (2005) report that such evidence is often absent at burglary scenes, and Hazelwood and Warren (2003) note that no or insufficient DNA evidence is found in a significant proportion of sexual offences. ...
... This means that, although forensic 'hits' might be valuable as evidence in court, they may not be available during the investigation and so cannot be used in the search for the offender. When forensic evidence is unavailable, behavioural analysis can be used to identify a linked series of offences (Bennell & Jones, 2005; Grubin et al., 2001; Hazelwood & Warren, 2003; Woodhams, Bull, & Hollin, 2007; Woodhams & Toye, 2007). This is known as case linkage. ...
... It is acknowledged that these findings are indicative rather than conclusive; however, they do highlight that analysts are routinely conducting case linkage on a variety of offence types (ranging from car theft to murder) to support the investigative process, and that they are using behaviour to identify series of offences. It is important to continue research in this area as failure to link offences accurately can waste police resources, delay the investigative process and/or reduce the chances of apprehending the offender (Bennell, Bloomfield, Snook, Taylor, & Barnes, 2010; Grubin et al., 2001). It is, therefore, important that the academic community continues to support case linkage work. ...
Comparative Case Analysis (CCA), typically conducted by crime analysts, uses crime scene behaviours to try to identify series of crimes committed by the same offender. Accurate identification of series of offences allows the police to pool resources and evidence, thereby boosting the potential to identify and apprehend the offender. This paper discusses the results of a survey of a sample of crime analysts working in two UK police forces about their views and experiences of CCA. The results focus on how CCA is conducted, what evidence and information is considered, and how useful CCA is to criminal investigation. Suggestions for how CCA might be developed further are also included.
... • Distances related to crime locations and the time span between offenses appear to be much more accurate predictors of crime linkages than actual modus operandi behavior, at least for some crime types, particularly volume crime (e.g., Bennell & Jones, 2005;Goodwill & Alison, 2006;Markson, Woodhams, & Bond, 2010;Tonkin, Santtila, & Bull, 2011; see Chapters 2 and 5). This raises the question of whether it is necessary to code for a large number of behaviors in police databases for the purpose of carrying out crime linkage analysis instead of relying on a smaller, but more reliable number of offense characteristics (Grubin, Kelly, & Brunsdon, 2001;Santtila et al., 2008). * * However, it should be noted, as Bennell et al. (2014) pointed out, that researchers have mostly focused on behavioral information and have tended to neglect other available nonbehavioral features (such as ethnicity, distinctive physical features, type of clothing, vehicle characteristics, and weapon description) that could potentially play a pivotal role in real-life crime linkage and that are stored in such databases. ...
... • Some linkage studies have excluded from their analyses very common and also infrequent, or rare behaviors (e.g., Grubin et al., 2001;Sorochinski & Salfati, 2010;Woodhams, Hollin, & Bull, 2008;Woodhams & Toye, 2007). * However, in practice, an atypical behavior could be crucial in linking a series together, if that behavior was exhibited in a consistent fashion by an offender. ...
... * However, in practice, an atypical behavior could be crucial in linking a series together, if that behavior was exhibited in a consistent fashion by an offender. • At least some serial offenders appear to behave less consistently than others (e.g., Bootsma & Eshof, 2006;Deslauriers-Varin & Beauregard, 2010;Grubin et al., 2001;Harbers, Deslauriers-Varin, Beauregard, & van der Kemp, 2012;Sorochinski & Salfati, 2010). This presents a problem for practitioners who, at present, have no evidence-based means of determining whether the series with which they are concerned is the work of a consistent or inconsistent offender. ...
... Prior studies also revealed that it is possible to successfully distinguish between linked and unlinked crimes on the basis of the offender's behaviours displayed at the crime scene (e.g. Bennell & Jones, 2005; Grubin et al., 2001; Markson et al., 2010; Melnyk et al., 2011; Tonkin, Woodhams, ...
... Serial sex offenders and crime series patterns 257 decreases when looking at longer series of crimes; and (3) serial offenders should display a higher level of consistency later in their series (or career) owing to their increasing knowledge and experience (e.g. Alison, Goodwill, Almond, van den Heuvel, and Winter, 2010; Blumstein et al., 1986; Grubin et al., 2001; Sullivan et al., 2006; Woodhams & Labuschagne, 2012b). ...
... Prior studies also revealed that it is possible to successfully distinguish between linked and unlinked crimes on the basis of the offender's behaviours displayed at the crime scene (e.g. Bennell & Jones, 2005; Grubin et al., 2001; Markson et al., 2010; Melnyk et al., 2011; Tonkin, Woodhams, Bull, Bond, & Palmer, 2011). 256 N. Deslauriers-Varin and E. Beauregard A more limited number of studies have specifically focused on testing the behavioural consistency assumption. ...
... Establishing that a number of offences are attributable to the same person supports the implementation of efficient and productive investigative strategies (Labuschagne, 2012;Santtila, Junkkila, & Sandnabba, 2005), for example, pooling information from all the crime scenes (Bennell et al., 2009), which can lead to faster identification and apprehension of the offender and/or strengthening the evidential case for court (Woodhams, Bull, & Hollin, 2007a). Linking offences can be relatively simple if forensic and/or physical evidence is found at the scene (Grubin, Kelly, & Brunsdon, 2001). However, forensic evidence is often lacking (Ewart, Oatley, & Burn, 2005;Hazelwood & Warren, 2003). ...
... However, forensic evidence is often lacking (Ewart, Oatley, & Burn, 2005;Hazelwood & Warren, 2003). When this is the case, behavioural analysis may be used to identify a linked series of offences (Bennell & Jones, 2005;Grubin et al., 2001;Hazelwood & Warren, 2003;Woodhams et al., 2007a;Woodhams & Toye, 2007). This is known as case linkage. ...
... Taken together, these assumptions allow individual offenders' offences to be (1) linked together and (2) distinguished from offences committed by other offenders. Evidence of behavioural consistency has been found for a range of offence types including sexual assault (Grubin et al., 2001), homicide (Salfati & Bateman, 2005), arson (Santtila et al., 2004), burglary (Bennell & Canter, 2002;Bennell & Jones, 2005;Markson, Woodhams, & Bond, 2010), vehicle crime (Tonkin, Grant, & Bond, 2008), and commercial robbery (Woodhams & Toye, 2007). Evidence has also been found in support of behavioural distinctiveness (Bennell & Canter, 2002;Bennell & Jones, 2005;Bennell, Gauthier, Gauthier, Melnyk, & Musolino, 2010;Grubin et al., 2001;Santtila, et al., 2004;Santtila, et al., 2005;Woodhams & Toye, 2007). ...
Case linkage uses crime scene behaviours to identify series of crimes committed by the same offender. This paper tests the underlying assumptions of case linkage (behavioural consistency and behavioural distinctiveness) by comparing the behavioural similarity of linked pairs of offences (i.e. two offences committed by the same offender) with the behavioural similarity of unlinked pairs of offences (i.e. two offences committed by different offenders). It is hypothesised that linked pairs will be more behaviourally similar than unlinked pairs thereby providing evidence for the two assumptions. The current research uses logistic regression and receiver operating characteristic analyses to explore which behaviours can be used to reliably link personal robbery offences using a sample of 166 solved offences committed by 83 offenders. The method of generating unlinked pairs is then refined to reflect how the police work at a local level, and the success of predictive factors re‐tested. Both phases of the research provide evidence of behavioural consistency and behavioural distinctiveness with linked pairs displaying more similarity than unlinked pairs across a range of behavioural domains. Inter‐crime distance and target selection emerge as the most useful linkage factors with promising results also found for temporal proximity and control. No evidence was found to indicate that the property stolen is useful for linkage. Copyright © 2012 John Wiley & Sons, Ltd.
... Over the last few years, the field of forensics has made dramatic scientific advancements in DNA methodologies, analyses of methods of evidence, and the complexity of related databases. It has generally been proposed that the most dependable method for distinguishing crimes carried out by a specific offender is by comprehensively collecting and analyzing physical evidence at the crime scene (Grubin, Kelly & Brunsdon, 2001). One rather effective option has been DNA profiling. ...
... The basis of this analysis typically relies on the victim's account of the crime. Next the analyst would attempt to identify and specify the pertinent behaviors in one incident in order to match it to other available crime reports (Grubin et al., 2001). There has been some discussion concerning whether particular behaviors which contribute to a crime's 'modus operandus,' which are clearly related to the offender's attempt to commit an offense effectively, ought to be utilized in the evaluation to connect crimes (Douglas & Munn, 1992), since modus operandus is a learned behavior and suitable to change. ...
... crime series where physical trace evidence is lacking or is costly or timeconsuming to process, pooling evidence from multiple crime scenes, and enhancing victim credibility (Davies, 1991;Grubin, Kelly, & Brunsdon, 2001;Labuschagne, 2015). However, errors in linkage prediction can misdirect investigative efforts and unnecessarily increase public fear of a serial offender being active in the area (Grubin et al., 2001). ...
... crime series where physical trace evidence is lacking or is costly or timeconsuming to process, pooling evidence from multiple crime scenes, and enhancing victim credibility (Davies, 1991;Grubin, Kelly, & Brunsdon, 2001;Labuschagne, 2015). However, errors in linkage prediction can misdirect investigative efforts and unnecessarily increase public fear of a serial offender being active in the area (Grubin et al., 2001). ...
Purpose
To conduct a test of the principles underpinning crime linkage (behavioural consistency and distinctiveness) with a sample more closely reflecting the volume and nature of sexual crimes with which practitioners work, and to assess whether solved series are characterized by greater behavioural similarity than unsolved series.
Method
A sample of 3,364 sexual crimes (including 668 series) was collated from five countries. For the first time, the sample included solved and unsolved but linked‐by‐DNA sexual offence series, as well as solved one‐off offences. All possible crime pairings in the data set were created, and the degree of similarity in crime scene behaviour shared by the crimes in each pair was quantified using Jaccard's coefficient. The ability to distinguish same‐offender and different‐offender pairs using similarity in crime scene behaviour was assessed using Receiver Operating Characteristic analysis. The relative amount of behavioural similarity and distinctiveness seen in solved and unsolved crime pairs was assessed.
Results
An Area Under the Curve of .86 was found, which represents an excellent level of discrimination accuracy. This decreased to .85 when using a data set that contained one‐off offences, and both one‐off offences and unsolved crime series. Discrimination accuracy also decreased when using a sample composed solely of unsolved but linked‐by‐DNA series (AUC = .79).
Conclusions
Crime linkage is practised by police forces globally, and its use in legal proceedings requires demonstration that its underlying principles are reliable. Support was found for its two underpinning principles with a more ecologically valid sample.
... To date, varying degrees of breadth and focus on offence behaviours have been employed by researchers to identify key features of a crime (Goodwill, Alison & Beech, 2009;Grubin, Kelly, & Brunsdon, 2001;Sorochinski & Salfati, 2010). Importantly, some studies subdivided offenders' MO into aspects based on temporal sequencing of behaviours (Santtila et al., 2005;Santtila et al., 2008), allowing for a nuanced understanding of what is occurring at various stages of the offense. ...
... Behaviours occurring at high frequency (present in more than 80% of cases) were removed, as they have been found to be poor discriminators between offenders. Likewise, behaviours occurring at low frequency (present in less than 10% of cases) were eliminated, as they are too rare to be generalizable (Grubin, Kelly, & Ayis, 1997;Grubin et al., 2001). ...
The present study investigated behavioural consistency across sexual offending. Variations in behavioural consistency may arise from an increased influence of situational and contextual aspects. However, there is paucity of research exploring variations in behavioural consistency relative to the temporal sequence of the behaviour (e.g., occurring prior to or during the offence). A sample of 49 male serial stranger sexual offenders responsible for 147 offences across four temporal phases of a sexual offence was used in the current study. For each offence, four crime phases were identified: 1) pre-crime, 2) victim selection, 3) approach, and 4) assault. Behavioural consistency within and across offence series were examined utilizing Jaccard’s Coefficient and Receiver Operating Characteristics (ROC). Results indicated a high degree of behavioural consistency across all crime aspects; behaviours that were more dependent on situational influences were inherently less predictable and demonstrated to be less consistent. Further, increased behavioural consistency was associated with offender characteristics of a more stable nature. The implications of these findings are discussed.
... The success of linkage analysis rests on three primary assumptions (Bennell and Jones, 2005;Goodwill and Alison, 2006;Grubin et al., 2001;Woodhams et al., 2007a). ...
... The first is that the criminals act consistently. While there might be slight variations in a criminal's behavior as the current goals, situational characteristics, and past learning influence each outcome (Woodhams et al., 2007b), a large body of literature suggests that there is sufficient consistency in some behavioral variables (especially site selection) to allow successful linkage analysis (Bennell and Canter, 2002;Bennell and Jones, 2005;Bernasco, 2008;Bouhana et al., 2014;Deslauriers-Varin and Beauregard, 2013;Goodwill and Alison, 2006;Grubin et al., 2001;Harbers et al., 2012;Johnson et al., 2009;Tonkin et al., 2008;Woodhams and Toye, 2007). ...
The object of this paper is to develop a statistical approach to criminal linkage analysis that discovers and groups crime events that share a common offender and prioritizes suspects for further investigation. Bayes factors are used to describe the strength of evidence that two crimes are linked. Using concepts from agglomerative hierarchical clustering, the Bayes factors for crime pairs are combined to provide similarity measures for comparing two crime series. This facilitates crime series clustering, crime series identification, and suspect prioritization. The ability of our models to make correct linkages and predictions is demonstrated under a variety of real-world scenarios with a large number of solved and unsolved breaking and entering crimes. For example, a naive Bayes model for pairwise case linkage can identify 82% of actual linkages with a 5% false positive rate. For crime series identification, 74%-89% of the additional crimes in a crime series can be identified from a ranked list of 50 incidents.
... Finally, although we found that many offenses where a wrongful conviction occurred were behaviorally consistent with the rest of the series, at least a quarter were not. This is in line with previous research on behavioral consistency in violent crime (e.g., Grubin et al., 2001;Hazelwood et al., 1989;Sorochinski andSalfati, 2010, 2018;Salfati and Sorochinski, 2019) and suggests that further research efforts are needed to develop investigative models for serial crime that take into account the dynamic nature of behavior in this type of offending. It is also important to further link the investigative psychology methods to the issues commonly observed in cases of wrongful conviction. ...
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.
... As with any repeated behaviours, some of these sequences may become automatic or habitual. Many cold cases homicides, however, do not involve serial killers, whose crimes can often be linked through a number of other established methods [15,16]. An additional strength of crime script analysis is the ability to investigate individual crimes and compare them to a database of other, though not identical, substantively similar cases [17]. ...
Criminal cases go cold when investigative leads or forensic testing does not lead to a successful arrest. In these cases, investigators are often keen to use novel methods to derive fresh ideas or insights. Recently, academics from a range of fields, including Psychology, Criminology, and Forensic Sciences have developed a range of new methods and tests to assist with police investigations. The current paper outlines a novel approach to assisting with police cold case investigations: Crime Script Sequencing. The new method combines two leading temporal methods, Crime Script Analysis and Behaviour Sequence Analysis. A real-world cold case, the bombing of Canadian Pacific Airlines Fight 21, is presented and analysed using Crime Script Sequencing to offer readers a guide of how to use the method for other investigations. Impacts, insights, and potential future developments of the method are outlined.
... A range of different statistical techniques are used to assess the underlying principles of crime linkage with samples of sexual offenses. Some studies measure the degree of similarity between two or more crimes using all crime scene behavior in one measurement (e.g., when calculating a similarity coefficient, such as Jaccard's coefficient, from all modus operandi (MO) behavior; e.g., Bennell et al., 2009;Davidson & Petherick, 2020;Woodhams et al., 2019), whereas other studies first group individual crime scene behaviors into domains or themes, which then form the basis for descriptive statistics regarding consistency (e.g., Grubin et al., 2001;Sorochinski & Salfati, 2018). Further some studies have calculated a similarity coefficient for each individual crime scene behavior (Deslauriers-Varin & Beauregard, 2014;Harbers et al., 2012). ...
Crime linkage can be a useful tool in the investigation of sexual offenses when other, physical evidence is unavailable or too costly to process. It involves identifying behavior that is both consistent and distinctive, and thus forms an identifiable pattern through which a series of offenses committed by the same offender can be distinguished. While there is a substantial body of research to support the principles of crime linkage, samples often contain only one type of sexual offense, and further research is needed into offenses such as voyeurism and exhibitionism. In practice, there are a number of ways in which crime linkage can be conducted, and a variety of terms are used to describe these different processes. While writings from practitioners provide insight into how crime linkage is conducted, research now needs to focus more on systematically mapping its practice and documenting procedural differences. There are also a number of additional considerations that require further research attention where the practice of crime linkage is concerned, such as the utility of computerised databases designed to assist with the process, the human decision-making element of linking and how bias can affect this, and the effects of expertise and training on linkage efficacy.
... In crime linkage analysis, information from crime scenes are collected, coded and processed in an appropriate way to interpret logically [1,2]. After coding the crimes, they are compared depending upon the evidences found on the crime scenes. ...
Serial Crimes cost a lot to our society and leave very appalling impact on our society in psychological level. Furthermore, the investigations are often very troublesome in the absence of reliable evidences. From a large number of criminal cases of similar types it is difficult to find the crimes that were committed by the same offenders. Crime linkage is the step by step process by which an investigator studies and detects the crimes related by common offenders. In this paper, a new idea of resemblance among a set of intuitionistic fuzzy set has been introduced. In addition, an intuitionistic fuzzy multi criteria decision making approach has been used to perform crime linkage analysis. This methodology will enable an investigator to find degree of extent for sharing of a common offender or offenders.
... The issue of identifying a more restricted variable set for consistency analysis that enables both subtype differentiation and the use of behaviors that are not as influenced by situational factors was followed up by Sorochinski and Salfati (2010). They aimed to subject variables that were stated in early work as being important in establishing consistency (e.g., Bateman & Salfati, 2007;Canter et al., 2004;Grubin, Kelly, & Brunsdon, 2001;Hickey, 2006;Ressler et al., 1986;Salfati & Bateman, 2005) to empirical investigation. These related to behaviors hypothesized to display physical evidence of offender cognition. ...
... It has also been purposefully applied in nontraditional fields such as counterterrorism, interviews and interrogation, risk analysis and management for sentencing, parole and expert testimony in trials. When the process of linking cases (called case linkage and explained before) is correct, it is a great contribution to police investigation and reduces the number of suspects (Grubin, Kelly & Brunsdon, 2001). However, an incorrect case linkage can lead to a wrongful conviction. ...
Offender profiling has been well known for the general public because of how it is portrayed and represented in media, movies, TV shows and in the news. However, the reality is sometimes far behind the myths and that is one of the reasons why it is often misinterpreted and misunderstood. Moreover, even though it has been well developed, researched and successful in some cases, profiling still has its limits and has been criticized a lot, mostly because of its lack of evidence and accuracy, as well as the lack of empirical research (but the other reasons will be developed in the last part of the literature review). As there is so much to say about profiling, this dissertation will look at three different linked topics in order to come up with three research questions to be analyzed and answered. Thus, the purpose of this study is to take a closer and deeper look at general profiling, especially in the United States, the United Kingdom and France, and extend the research on the matter, as well as analyze how it affected (both in a good way and also how it was criticized) the criminal justice system and the psychology fields. The second purpose is to rely on how the media portrayed criminals and how it created such fascination and myths behind what it is actually in reality; why is criminal profiling and investigative techniques such a big deal for the general population and why is it a fear but yet a fascination for them? Fueled by media, shows and movies, crime is an interesting and intriguing topic for a lot of people, and especially how to get inside the criminal mind. Where is profiling going to? Why and how is profiling not standing still? Finally, the study will try to propose alternatives and solutions to improve its use internationally and in different fields. To this end, the research questions are as follow: • Is offender profiling still a credible method of investigation? • To what extent does the media oversell the ability of profiling? • What can be done in the future to improve and enhance the use of profiling methods? Forensic psychology is such a broad and diverse field, as well as the offender profiling topic. The three research questions that I have chosen would help me define the outline of my dissertation, as well as divide the different chapters. The research questions will be answered through the use of secondary and qualitative research, more specifically with documentary analysis primarily. That is to say, the review and analysis of documents (physical evidence with handbooks and training materials, personal documents such as newspapers, posts, reports, previous classes, and public records). After analyzing all the data and information collected through secondary research, there are a lot of common opinions on the subject, and the will to improve the methods, as well as informing the general population more on both the criminal justice system combined with the role that psychology plays in finding perpetrators of crimes and prevent them from happening in the near future. Critiques on profiling usually agree on the same issues and flaws, such as how the methods are conducted, how the topic is portrayed and influential, and most of the time, far from the reality.
... In Grubin et al. [4] it is noted that the most reliable means of establishing a link between offenses is by 'physical' evidence (e.g. DNA profiles/footwear evidence). ...
In de Zoete et al. (2015) a framework for the evaluation of evidence when an individual is a suspect of two separate offenses (based on Evett et al., 2006) is implemented using a Bayesian network. Here, we extend this to situations with multiple offenders. When we have multiple offenders, new questions arise: (1) Can we distinguish between the offenders, even if we do not know their identity? (2) Do we know that certain pieces of evidence originate from the same person? (3) Do we know the number of offenders? With the aid of a mock case example, we show that such subtle differences between situations can lead to substantially different conclusions in terms of posterior probabilities of a certain suspect being one of the offenders in a particular crime.
... For crime categories that involve serial offenders, i.e. where the offender commits two or more crimes of same type, law enforcement agencies strive to combine crimes committed by the same offender(s) into crime series [9] [16]. This allows investigators to get a more complete picture based on all information and evidence collected from the various crime scenes, compared to investigating each crime in isolation [18]. ...
Law enforcement agencies strive to link serial crimes, most preferably based on physical evidence, such as DNA or fingerprints, in order to solve criminal cases more efficiently. However, physical evidence is more common at crime scenes in some crime categories than others. For crime categories with relative low occurrence of physical evidence it could instead be possible to link related crimes using soft evidence based on the perpetrators' modus operandi (MO). However, crime linkage based on soft evidence is associated with considerably higher error-rates, i.e. crimes being incorrectly linked. In this study, we investigate the possibility of filtering erroneous crime links based on travel time between crimes using web-based direction services, more specifically Google maps. A filtering method has been designed, implemented and evaluated using two data sets of residential burglaries, one with known links between crimes, and one with estimated links based on soft evidence. The results show that the proposed route-based filtering method removed 79 % more erroneous crimes than the state-of-the-art method relying on Euclidean straight-line routes. Further, by analyzing travel times between crimes in known series it is indicated that burglars on average have up to 15 minutes for carrying out the actual burglary event.
... These challenges are compounded by the need for a focused investigation based on time and capacity restrictions (TerBeek et al, 2010: 32, 34). In a study conducted by Santtila, Junkkila and Sandnabba (2005: 101-102) on the behavioural linking of stranger rapes, the authors conclude by stating that their study, as well as previous studies (cf Grubin, Kelly & Brunsdon, 2001) confirm that rape is hardly a haphazard collection of behaviours. They argue that it has a consistent thematic structure that, amongst offenders, contributes to their differentiation. ...
This article evaluates the use of a rape matrix as a docket analysis tool in a sample of 94 closed and unsolved stranger rape cases reported in Port Elizabeth between 1 January 2007 and 31 January 2008. The study was initiated in January 2009 with the final interviews concluded during November 2013. The primary aim of this research was to determine the value of docket analysis in the identification of possible serial rape activity amongst a sample of unsolved stranger rape cases, and secondary, to analyse and evaluate investigative decision-making in these cases. The sample consisted of cases where a female victim was raped by a single male offender who remained unidentified. This research makes a significant contribution to the field of rape investigation. It does so by demonstrating and explicating the identification of five possible rape series amongst the sample of stranger rape cases that are indicative of serial rape activity. This research also
highlights shortcomings in the investigation of these cases, which hamper case linkage. Recommendations are made for more effective investigative strategies, management and identification of serial rape activity
amongst stranger rape cases.
... There was significant shrinkage observed in the residential burglary sample when applying the classification tree model from the training to test sample, which suggests that this model may not fully generalise to new cases. This is a particular problem in applied research where the ultimate aim is to develop predictive models that can be used to guide future investigations and where incorrect linkage decisions can significantly hinder an investigation (Grubin et al., 2001). Furthermore, it makes it difficult to provide an accurate estimate of the error rate one should expect when using the burglary ICT model to identify linked and unlinked crimes. ...
... Although the notion of behavioural consistency presents discomfort for some behaviourists, and the notion has been criticized (Mischel, 1973), there is both theoretical and empirical support for cross-situational consistency in criminal behaviour.Grubin et al. (2001)identified behavioural consistency in serial sexual offenders.Zamble and Porporino (1990)showed that prisoners responded similarly to a range of prison difficulties as they had problems outside the prison, and McDougal and colleagues (Clark et al., 1994;McDougal & Clark, 1991;McDougal et al., 1994) reported that prisoners reveal comp ...
IntroductionUsing OPB to Assess and Treat Violent OffendersAdditional Complicating Factors for OPB: Future Opportunities and NeedsConclusion
References
... Second, it must be available to investigators. For example, confessions, eyewitness testimony, physical and/or forensic evidence such as fibers, fingerprints, or DNA all may be highly effective at discerning linkages (Grubin et al., 2001). However, these types of evidence may be rare (Ewart, Oatley, & Burn, 2005;Hazelwood & Warren, 2003). ...
Probability-based methods have been shown to be useful in crime linkage analysis (the determination of which crimes were committed by the same offender). However, little consensus exists as to the value of specifically tailoring these methods to individual jurisdictions. Considering regional differences in routine activities, incorporating local information into crime linkage analysis may improve the effectiveness of linkage strategies. Using simulation methods, this study addresses the impact of regional variation in factors affecting criminal opportunity on crime linkage tools.
... Rainbow, 2014). For example, a successfully linked crime series can be investigated (and prosecuted) as a whole, compiling the evidence from the separate crimes against the offender (Grubin et al., 2001). It is also resource efficient: linking crimes by means of DNA, for example, is both costly and time consuming (Craik and Patrick, 1994), in addition to the fact that DNA evidence is not always readily available at the crime scene (Grubin et al., 1997). ...
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.
... However, research to date has failed to identify greater behavioral consistency indicative of expertise (e.g., Grubin, Kelly, Brunsdon, & Britain, 2001;Woodhams, Hollin, & Bull, 2008;Woodhams & Labuschagne, 2012). Woodhams and Labuschagne (2012) examined the similarities of pairs of rapes that were either linked (committed by the same offender) or unlinked (committed by different offenders). ...
Despite being over 15 years old researchers have been slow to adopt the competency or expertise perspective advocated by Ward (1999) as a complimentary viewpoint to the dominant deficit model of sexual offending. A growing body of research on the behavioral and cognitive impact of expertise suggests that it is timely to revisit the question of whether individuals can become expert at rape. This review summarizes the key points in Ward's theory and evaluates the scant research that could lend it support. The expertise perspective is a fertile area for future research and may provide a mechanism for explaining the relationship between explicit and implicit measures of distorted cognition. The review makes suggestions for future research and appraises the clinical implications of considering sexual aggressors as novices or experts.
... One objective is to cluster crime events that share a common offender or group of co-offenders. As an investigative tool, the results from clustering will allow crime analysts to operate more efficiently and effectively by jointly investigating crimes that are likely to share a common offender instead of investigating each crime individually (Grubin et al., 2001;. Clustering can also be useful for discovering previously unknown serial offenders or identifying additional crimes that are part of a series. ...
Statistical clustering of criminal events can be used by crime analysts to create lists of potential suspects for an unsolved crime, to identify groups of crimes that may have been committed by the same individuals or group of individuals, for offender profiling and for predicting future events. We propose a Bayesian model-based clustering approach for criminal events. Our approach is semisupervised, because the offender is known for a subset of the events, and utilizes spatiotemporal crime locations as well as crime features describing the offender's modus operandi. The hierarchical model naturally handles complex features that are often seen in crime data, including missing data, interval-censored event times and a mix of discrete and continuous variables. In addition, our Bayesian model produces posterior clustering probabilities which allow analysts to act on model output only as warranted. We illustrate the approach by using a large data set of burglaries in 2009–2010 in Baltimore County, Maryland.
... Rape is hardly a haphazard collection of behaviors. It has a consistent thematic structure which, amongst offenders, contributes to their differentiation (Santtila et al. 2005:101-102;Grubin, Kelly & Brunsdon 2001). Furthermore, the advantages of linking cases of serial stranger rape using behavioural information and multidimensional methods should not be underestimated, as this can be of practical use in the total absence of physical evidence and witness statements (Santtila et al. 2005:102;Hazelwood & Warren 2003:588). ...
This article explores the intricacies of modus operandi, signature and fantasy as distinctive behaviour in stranger rape cases involving child victims that were reported in Port Elizabeth, which were analysed by means of a rape matrix. The authors identified distinctive behaviour of offenders in two possible rape series’ involving child victims.
Consequently, the authors probe whether a more comprehensive investigation, which reflects an understanding of modus operandi, signature and fantasy behaviour, could have determined if both rape series were perpetrated by the same offender. The article, furthermore, explores examples of reported cases to illustrate how modus operandi, signature or fantasy can manifest amongst offenders, and, should this behaviour recur in a subsequent case, could be indicative of the same offender committing the crime. The findings suggest that the presence of these distinct behaviours in conjunction with aspects such as the geographic location and time of the rapes could be indicative of serial rape activity. The results obtained from the child rape cases in this study contribute to a practical understanding of how distinctive behaviour, indicative of serial rape activity, can be identified by practitioners, who provide response and investigative service to sexually abused children in a professional capacity, such as police officials, social workers and psychologists.
... The reliable inference of offender characteristics from crime scene behaviours to prioritise suspects in investigations is the aim of offender profiling (Egger, 1999; Goodwill & Alison, 2007; Kocsis et al., 2002). Offender profiling methods are typically utilised in cases where there is an inadequate or lack of physical evidence present at the crime scene such as DNA or fingerprints (Grubin, Kelly, & Brunsdon, 2001). Offender profiling employs a wide range of activities to apprehend and prioritise suspects, including crime scene behavioural analysis (Alison, Goodwill, Almond, Van den Heuvel, & Winter, 2010). ...
In a recent study of personal robbery, commissioned by the Home Office in the UK, a qualitative typology of robbery offences was proposed based on the approach used by the offender to commit the crime, consisting of four approach types: Blitz, Confrontation, Con, and Snatch. Conceptual inspection of the typology reveals that these proposed types may be hypothetically demarcated as the product of two latent dimensions: interaction (between the offender and the victim) and violence (used to threaten/harm the victim). The current paper utilises crime scene information from 72 incarcerated male offenders convicted of ‘street’ robbery to test this hypothesis. Convergent statistical analysis was utilised to test the structure of Smith's typology first using multidimensional scaling (MDS) and then principal component analysis (PCA). MDS and PCA analyses provided convergent support for the existence of the four robbery styles and the latent dimensions of interaction and violence. Implications of Smith's typological structure and latent behavioural dimensions on the conceptualisation and classification of robbery offences are discussed within the existing literature on ‘street’ robbery. Copyright © 2012 John Wiley & Sons, Ltd.
Exploring a specific type of sexual violence committed by a specific type of sexual offender, namely adult male on adult female stranger sexual violence, this book provides readers with an enhanced understanding of both the offences being committed and the offenders who commit them.
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
In the decade since the publication of the first edition of The Cambridge Handbook of Forensic Psychology, the field has expanded into areas such as social work and education, while maintaining the interest of criminal justice researchers and policy makers. This new edition provides cutting-edge and comprehensive coverage of the key theoretical perspectives, assessment methods, and interventions in forensic psychology. The chapters address substantive topics such as acquisitive crime, domestic violence, mass murder, and sexual violence, while also exploring emerging areas of research such as the expansion of cybercrime, particularly child sexual exploitation, as well as aspects of terrorism and radicalisation. Reflecting the global reach of forensic psychology and its wide range of perspectives, the international team of contributors emphasise diversity and cross-reference between adults, adolescents, and children to deliver a contemporary picture of the discipline.
This chapter explores the types of behaviour seen in sex offending. It covers how behaviour has been used to create typologies of offending, as well as how both internal factors – such as fantasy and offender characteristics, and external factors – such as the number of offenders present and the cultural influence on behaviour – can affect sex offender behaviour. It also explores how behaviour can be conceptualised as a pattern demonstrated across a series of offences, and the factors that can affect the consistency of this behaviour. Finally, this chapter outlines how our understanding of sex offender behaviour can contribute to the investigation, assessment, management, and treatment of sex offenders.
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.
This article describes how serial crimes are very interesting for study in the absence of proper and solid evidence. From a high volume of criminal cases of similar types, it is difficult to detect the crimes that were committed by the same offender or not. The process of linking of crimes which were committed by the same offender or offenders is called Crime Linkage Analysis. In this article, a new hesitant fuzzy distance measure has been introduced and a fuzzy multicriteria decision-making approach has been proposed to help Crime Linkage Analysis, which enables us to find to what extent a pair of crime shares a common offender or offenders.
This thoroughly updated and revised new edition provides an essential overview of a full range of psychological contributions to the understanding of crime and the processes of dealing with offenders and helping their victims. From the cognitive, developmental and social processes that influence a diverse range of crimes, including burglary, fraud, rape and murder, to the challenges faced by the police and courts in investigating crime or securing reliable testimony, the text is packed with pedagogical features that bring this fascinating subject to life. These include boxes highlighting key topics or issues around research methods, further reading and suggested essay titles. Also including chapters on rehabilitation in prisons and the psychology of victims, the text examines hot topics such as gang membership and terrorism, as well as discussing how psychology may better understand criminals and criminal behaviour in the future. It builds to a comprehensive and accessible introduction to the field. It will be ideal for students across psychology, criminology and socio-legal studies and law.
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.
This study examined the effectiveness of multiple correspondence analysis (MCA) for linking crimes. The data consisted of 720 incidents committed by 360 individual offenders of serial criminal sexual contact cases (i.e., rape and forced indecency). According to the measured similarity obtained from the Euclidean distance in the MCA configuration, a rank-score was assigned to each linked pair and unlinked pair. The validity of MCA for linking crimes was evaluated with a 10-fold cross-validation procedure and a receiver operating characteristic analysis. The t-test of rank scores showed a statistically significant difference between linked pairs and unlinked pairs (t(641.43) = −18.53, p < .001, d = 1.38). The value of the area under the receiver operating characteristic curve was 0.83 (95% CI = 0.80–0.86), indicating a high level of discriminative accuracy in distinguishing offences committed by the same person from those committed by different persons.
In recent years, profiling has moved to a more evidence-based approach, and into mainstream forensic psychology as the new discipline of Behavioural Investigative Advice. Furthermore, profiling in the United Kingdom has become a recognised profession. The chapter first considers white-collar offenders, including fraud offenders, and individual differences as well as some myths about white-collar offenders before focusing on empirical (both exploratory and comparative) studies of such offenders’ characteristics and their limitations. Attention then turns to the offender profiling concept as it has evolved over the years, outlining approaches to it (diagnostic evaluation, criminal investigative analysis, crime action profiling, investigative psychology and geographical profiling) before focusing on the feasibility of applying a recast notion of geographical profiling to internet fraudsters. The chapter concludes about the importance of a small number of characteristics of fraud offenders and how they could be utilized to reduce the risk of fraud but, also, makes suggestions for future research.
Problems of classification in the field of Investigative Psychology are defined and examples of each problem class are introduced. The problems addressed are behavioural differentiation, discrimination among alternatives, and prioritisation of investigative options. Contemporary solutions to these problems are presented that use smallest space analysis, receiver operating characteristic analysis, and probability functions.
When two or more crimes show specific similarities, such as a very distinct modus operandi, the probability that they were committed by the same offender becomes of interest. This probability depends on the degree of similarity and distinctiveness. We show how Bayesian networks can be used to model different evidential structures that can occur when linking crimes, and how they assist in understanding the complex underlying dependencies. That is, how evidence that is obtained in one case can be used in another and vice versa. The flip side of this is that the intuitive decision to "unlink" a case in which exculpatory evidence is obtained leads to serious overestimation of the strength of the remaining cases.
Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.
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.
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.
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