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Unravelling Crime Series Patterns amongst Serial Sex Offenders: Duration, Frequency, and Environmental Consistency
... Research, however, has shown that these criticisms are overstated (e.g., Deslauriers-Varin and Beauregard 2014b;Lussier, Bouchard, and Beauregard 2011;Lussier and Mathesius 2012). While the concept of professional criminals remains unclear and elusive, it embodies a subculture or a criminal milieu of serious and skilled offenders (Bouchard and Nguyen 2011). ...
... In fact, specialization may be more evident as the criminal career progresses and becomes more established (e.g., Farrington 1986) and as persistent offenders become more aware of crime contingencies. This suggests that older and more experienced offenders are more specialized in offending (e.g., Blumstein et al. 1988;Brennan et al. 1989;Deslauriers-Varin and Beauregard 2014b;Lussier et al. 2011). ...
... To date, empirical studies in the field of behavioral consistency have been conducted on a limited set of criminal behaviors and often on the most extreme forms of crime. Indeed, the focus of most studies has been on violent crimes, such as sexual offences (e.g., Sjöstedt et al. 2004;Woodhams, Grant, and Price 2007;Woodhams, Hollin, and Bull 2008), sexual assault (e.g., Davies 1992;Deslauriers-Varin 2013, 2014a, 2014bGrubin, Kelly, and Brunsdon 2001;Harbers et al. 2012;Lundrigan, Czarnomski, and Wilson 2010), rape (Davies, Wittebrood, and Jackson 1997;Santtila, Junkkila, and Sandnabba 2005;Labuschagne 2012a, 2012b), homicide (e.g., Bateman and Salfati 2007;Melnyk et al. 2011;Salfati and Bateman 2005;Santtila et al. 2008;Sorochinski and Salfati 2010), as well as sexual homicide (e.g., Schlesinger et al. 2010). The growing popularity of crime linkage, however, has led some researchers to explore the utility of crime linkage with a wider range of crime types, such as burglary (e.g., Bennell and Canter 2002;Bennell and Jones 2005;Bernasco 2008;Markson et al. 2010;Melnyk et al. 2011;Tonkin, Santtila, and Bull 2012;Toye 2007), car theft (e.g., Tonkin et al. 2008), and arson (Ellingwood et al. 2013;Santtila, Fritzon, and Tamelander 2004). ...
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... Research, however, has shown that these criticisms are overstated (e.g., Deslauriers-Varin and Beauregard 2014b;Lussier, Bouchard, and Beauregard 2011;Lussier and Mathesius 2012). While the concept of professional criminals remains unclear and elusive, it embodies a subculture or a criminal milieu of serious and skilled offenders (Bouchard and Nguyen 2011). ...
... In fact, specialization may be more evident as the criminal career progresses and becomes more established (e.g., Farrington 1986) and as persistent offenders become more aware of crime contingencies. This suggests that older and more experienced offenders are more specialized in offending (e.g., Blumstein et al. 1988;Brennan et al. 1989;Deslauriers-Varin and Beauregard 2014b;Lussier et al. 2011). ...
... To date, empirical studies in the field of behavioral consistency have been conducted on a limited set of criminal behaviors and often on the most extreme forms of crime. Indeed, the focus of most studies has been on violent crimes, such as sexual offences (e.g., Sjöstedt et al. 2004;Woodhams, Grant, and Price 2007;Woodhams, Hollin, and Bull 2008), sexual assault (e.g., Davies 1992;Deslauriers-Varin 2013, 2014a, 2014bGrubin, Kelly, and Brunsdon 2001;Harbers et al. 2012;Lundrigan, Czarnomski, and Wilson 2010), rape (Davies, Wittebrood, and Jackson 1997;Santtila, Junkkila, and Sandnabba 2005;Labuschagne 2012a, 2012b), homicide (e.g., Bateman and Salfati 2007;Melnyk et al. 2011;Salfati and Bateman 2005;Santtila et al. 2008;Sorochinski and Salfati 2010), as well as sexual homicide (e.g., Schlesinger et al. 2010). The growing popularity of crime linkage, however, has led some researchers to explore the utility of crime linkage with a wider range of crime types, such as burglary (e.g., Bennell and Canter 2002;Bennell and Jones 2005;Bernasco 2008;Markson et al. 2010;Melnyk et al. 2011;Tonkin, Santtila, and Bull 2012;Toye 2007), car theft (e.g., Tonkin et al. 2008), and arson (Ellingwood et al. 2013;Santtila, Fritzon, and Tamelander 2004). ...
Crime specialization is one of the most researched and often-debated criminal career parameters. To date, the concept of specialization has been approached mainly from a static viewpoint whereby crime specialization and criminal versatility have been conceptualized as two opposite end of a continuum. Emerging research based on longitudinal data, however, has led to the emergence of a dynamic-oriented perspective where specialization and versatility can occur during one’s career. In this essay, the evolution of the concept of crime specialization is highlighted along with associated theoretical, conceptual, methodological, and empirical issues stemming from this gradual change. Policy implications and directions for future research on the development of criminal careers are highlighted.
... The inspection of sex offender's criminal behavior has led researchers to conclude that they make a series of rational decisions -just like other criminals -to achieve their goal (i.e., sexual gratification) through illicit means, such as victim selection, determining crime location, planning victim transport to the crime site, and choosing a method of attack (e.g., Beauregard et al., 2007aBeauregard et al., , 2007bDeslauriers-Varin & Beauregard, 2014). The rational and strategic sex offender (Beauregard & Leclerc, 2007) may use deception, manipulation, alcohol/drugs, coercion, threat and/or physical violence to obtain sexual gratification (e.g., Koss et al., 1987;Leclerc et al., 2009). ...
... Their findings showed that the most productive offenders were older, in a stable relationship with an adult partner, involved in a high number of sexual crime events, and they tended to limit their number of victims targeting mainly children, including their own. Most importantly, "successful" sex offenders were more efficient at delaying detection (up to 40 years), which was partly explained by their ability to avoid the use of serious physical violence combined with their victim selection and crime specialization (see also Deslauriers-Varin & Beauregard, 2014). The study further showed that offending productivity, when defined in terms of crime events, was unrelated to sentencing, suggesting that the successful sex offender is not really detected, even after being convicted for some offenses, nor is he handled in a way that may deter him from sexually reoffending in the future. ...
Criminal investigations typically oppose two main actors: the offender – who takes precautions to avoid leaving evidence – and criminal investigators, who must act in light of the evidence at their disposal. Although successfully engaging in criminality does not require special skills, as evidenced by the lack of premeditation involved in most crimes, this apparent absence in decision making is not always an indication of lack of skills and planning on behalf of the offender. Rather, it demonstrates that some offenders have developed in-depth knowledge and skills to assess various situations and opportunities, which enables them to make quicker and more efficient decisions – also known as criminal expertise. The notion of expertise in crime is directly linked to rational choice theory, as offenders develop skills to assess and respond to crime opportunities through practice. While assessing the risks and rewards associated with committing the crime, offenders will make a decision to act a certain way in order to improve the rewards while reducing the risks of getting caught. This chapter argues that similar to general offenders, sex offenders have developed a criminal expertise aimed at avoiding police detection. After discussing the concept of criminal expertise in general, the chapter examines this notion for sex offenders specifically. Moreover, the chapter reviews important notions related to offenders’ decision-making during the crime-commission process and how these may impact the ability of avoiding police detection. Finally, the chapter reviews how the investigation of sexual crimes may be partly influenced by criminal expertise.
... To this end, Figure 1 details the most representative and consistently replicated offender profiles for sex offenders to date. Notably, these profiles have been identified in multiple studies, drawing upon varied samples, measures, and approaches, increasing confidence in the validity, reliability, and applicability of the resultant profiles (see Beauregard & Field, 2008;Beauregard & Field, 2008;Beech et al., 2005;Canter et al., 2003;Deslauriers-Varin & Beauregard, 2014;Gerard, Mormont, & Kocsis, 2007;Hazelwood & Warren, 2000;Häkkänen, Lindlöf, & Santtila, 2004;House, 1997;Kerr et al., 2013;Kocsis, 1999;Kocsis, Cooksey, & Irwin, 2002;Ressler et al., 1986;Ressler, Burgess, & Douglas, 1988;Stefanska et al., 2015). ...
... The third most common profile of sex offenses was the opportunistic sub-type (Deslauriers-Varin & Beauregard, 2014;Gerard et al., 2007;Keppel & Walter, 1999), characterized by high levels of impulsivity and little premeditation, in line with disorganized offense. However, opportunistic offenses lack several defining features of the disorganized profile, as they are less chaotic or motivated by anger/fury and sexual intimacy. ...
Offender profiling has been used by law enforcement agencies around the world for decades. Following homicide, offenses involving sexual assault are the second most common type of crime examined in offender profiling. Profiling sex crimes has successfully assisted investigators to find and convict sexual offenders and to deter future crimes. In this chapter, we focus on studies that developed profiles of sexual homicide and sexual assault to identify the personality characteristics, backgrounds, and mental states among offenders for these crimes, as well as analyze the similarities among sexual homicide and assault offenders, unique characteristics of these offenders, and how law enforcement can use these profiles to catch and prevent these offenders in the future.
... One of the most interesting breakthroughs of criminal-career research in the field of sexual offending has been the measurement and the identification of long-term offending trajectories (e.g., Deslauriers-Varin & Beauregard, 2014;Lussier, Tzoumakis, Cale, & Amirault, 2010). ...
... Based on research using a criminal-career framework, it is now believed that such conclusions are misleading and do not capture the various offending trajectories characterizing both these groups (e.g., Francis et al., 2014;McCuish et al., 2015). In fact, even criminal-career research on serial sexual offenders has shown the intermittency and the diversity of these individuals' life-course patterns of sexual offending (Deslauriers-Varin & Beauregard, 2014) to be reminiscent of well-known general offending trajectories (e.g., Piquero, 2008). Research has also shown that sexual offending characteristics (e.g., victim characteristics, modus operandi, pre-crime factors) among these sexual-offender subtypes are informative of their sexual criminal-career activity (e.g., Cale & Lussier, 2012 ...
This chapter introduces the scientific literature on the life‐course development of antisocial and criminal behavior. It provides a review of key concepts and findings related to criminal‐career research, developmental criminology, and life‐course criminology. chapter examines some of the implications of such research for the description, explanation, and prevention of sexual offending. The criminal‐career approach is an important line of research that helped establish the conceptual and methodological foundations of the Developmental life‐course (DLC) perspective. Developmental criminology is a research paradigm concerned with the description and explanation of the precursors of adult criminal behavior. Life‐course criminology is primarily rooted in sociological perspectives concerned with how and why people change their behavior, including why desistance from offending occurs. A central principle of life‐course criminology is that informal social controls act as turning points that promote desistance.
... For the most part, sexual crimes in the sample were the primary motive for committing the crime, most injuries, judging by the case materials, were the result of an attempt to subdue and demoralise the victim. Deslauriers-Varin and Beauregard (2014) provide data that there are 2 types of serial sex offenders: those who specialise in sexual crimes and those who commit various types of crimes. Heiler et al. (2023) conducted an assessment of the criminal specialisation of criminals, covering 580 results of anonymous criminal cases. ...
Background. The relevance of preventing and solving such crimes is growing, and a special place in this is occupied by forensic research, in particular, the analysis of modus operandi of criminals. The purpose of the study was to investigate the modus operandi of serial sex offenders. Methods. The main method of research was criminal profiling based on 50 cases in the Unified State Register of Court Decisions, for which the verdict was passed. Results. A number of indicators were investigated, including the characteristic method of attack, the choice of the victim, how the contact with the victim was established, and the method of committing the offence. As a result, it was established that criminals can be divided into two characteristic types according to modus operandi: the first type carries out a sudden attack or pursuit of the victim, is characterised by a violent method of attack, and the crime is often accompanied by bodily harm. The psycho-emotional portrait of attackers of this type is characterised by greater impulsivity and spontaneity of actions. The main motivation for committing a crime is to satisfy a sexual urge. Criminals of the second cluster tend to commit planned attacks, mostly indoors, establish contact with the victim, resort to manipulation and threats. They have a less pronounced passion and tend to plan crimes. The dominant motivation can be either sexual or the satisfaction of sadistic tendencies and dominance. Conclusions. This study focuses on the characteristic modus operandi and psychological characteristics of criminals who commit serial sexual offences.
... La consistencia conductual en delincuentes seriales ha sido estudiada en el caso de homicidios (Salfati & Bateman, 2005;Bateman & Salfati, 2007;Sorochinski & Salfati, 2010;Salfati, Horning, Sorochinski & Labuschagne, 2015), intrusión en propiedades con fines de robo (Bouhana, Johnson & Porter, 2016;Fox & Farrington, 2016), y agresores sexuales (Lundrigan, Czarnomski, & Wilson, 2010;Harbers, Deslauriers-Varin, Beauregard & Kemp, 2012;Deslauriers-Varin & Beauregard, 2013, 2014a, 2014bHewitt & Beauregard, 2014;Oziel, Goodwill & Beauregard, 2015). En general, estos estudios concluyen, de una forma metodológicamente aceptable, que los delincuentes seriales tienden a repetir sus conductas crimen tras crimen (Janosch & Soto, 2018; Janosch, Pérez-Fernández & Soto-Castro, 2018a y 2018b; Janosch, Pérez-Fernández & Soto-Castro, 2020; Pérez-Ramírez, Giménez-Salinas, González-Álvarez, Soto-Castro, 2021). ...
Propósito: Estudiar la consistencia en las conductas de los agresores sexuales desconocidos y seriales en la escena del crimen, y la influencia de los factores situacionales. Método: Se analizan las conductas en la escena del crimen de 18 agresores sexuales desconocidos y seriales, que cometieron al menos 54 agresiones sexuales. Se han correlacionado con factores situacionales. Se ha estudiado también la consistencia de cada una de esas conductas. Resultados: Algunas conductas de los delincuentes están influidas por factores situacionales y, a la inversa, algunos factores situacionales pueden estar influidos por tales conductas. Algunas conductas que, prima facie, no están influenciadas por los factores situacionales son consistentes. Una excepción son las conductas sexuales del delincuente. Conclusión: Este análisis confirma, aunque limitadamente, relaciones conductuales esperables, pero nunca antes estudiadas, en una muestra española de agresores sexuales seriales y desconocidos.
... La consistencia conductual en delincuentes seriales ha sido estudiada en el caso de homicidios (Salfati & Bateman, 2005;Bateman & Salfati, 2007;Sorochinski & Salfati, 2010;Salfati, Horning, Sorochinski & Labuschagne, 2015), intrusión en propiedades con fines de robo (Bouhana, Johnson & Porter, 2016;Fox & Farrington, 2016), y agresores sexuales (Lundrigan, Czarnomski, & Wilson, 2010;Harbers, Deslauriers-Varin, Beauregard & Kemp, 2012;Deslauriers-Varin & Beauregard, 2013, 2014a, 2014bHewitt & Beauregard, 2014;Oziel, Goodwill & Beauregard, 2015). En general, estos estudios concluyen, de una forma metodológicamente aceptable, que los delincuentes seriales tienden a repetir sus conductas crimen tras crimen (Janosch & Soto, 2018; Janosch, Pérez-Fernández & Soto-Castro, 2018a y 2018b; Janosch, Pérez-Fernández & Soto-Castro, 2020; Pérez-Ramírez, Giménez-Salinas, González-Álvarez, Soto-Castro, 2021). ...
Filiación Institucional (1) Resumen Propósito: Estudiar la consistencia en las conductas de los agresores sexuales desconocidos y seriales en la escena del crimen, y la influencia de los factores situacionales. Método: Se analizan las conductas en la escena del crimen de 18 agresores sexuales desconocidos y seriales, que cometieron al menos 54 agresiones sexuales. Se han correlacionado con factores situacionales. Se ha estudiado también la consistencia de cada una de esas conductas. Resultados: Algunas conductas de los delincuentes están influidas por factores situacionales y, a la inversa, algunos factores situacionales pueden estar influidos por tales conductas. Algunas conductas que, prima facie, no están influenciadas por los factores situacionales son consistentes. Una excepción son las conductas sexuales del delincuente. Conclusión: Este análisis confirma, aunque limitadamente, relaciones conductuales esperables, pero nunca estudiadas, en una muestra española de agresores sexuales seriales y desconocidos. Palabras Clave Agresión sexual, desconocido, decisiones conductuales, situación, consistencia conductual. Abstract Purpose: To study the consistency in crime scene behaviors of unknown and serial sexual offenders and the influence of situational factors. Methods: The crime scene behaviors of 18 unknown and serial sexual offenders, who committed at least 54 sexual assaults, were analyzed. They have been correlated with situational factors. The consistency of each of these behaviors was also studied. Results: Some offenders' behaviors are influenced by situational factors and, conversely, some situational factors may be influenced by such behaviors. Some behaviors that, prima facie, are not influenced by situational factors are consistent. An exception is offender sexual behaviors. Conclusion: This analysis confirms, albeit to a limited extent, expected but never studied behavioral relationships in a Spanish sample of serial and unknown sex offenders.
... 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). Studies that have compared the relative merit of including all crime scene behavior in one measurement of behavioral similarity to using domains or themes of behavior have concluded that predictions of crime linkage are more accurate when using all crime scene behaviors together (e.g., Bennell et al., 2009;Oziel et al., 2015). ...
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.
... Furthermore, most of these studies looked at the influence of interrogation techniques specifically or are based on a fairly homogenous sample of sex crime perpetrators, typically composed of individuals who have committed a contact crime such as sexual assault. This is particularly problematic considering that studies tend to show that sexual offenders are not a homogeneous group (Deslauriers-Varin & Beauregard, 2014;Knight & Prentky, 1990), and might explain why no factor or technique appears to be uniquely valuable with this subgroup of offenders (compared to general samples of offenders) when it comes to favoring confession, cooperation, and the gathering of truthful information. ...
Establishing if a crime occurred and, ultimately, proving guilt can be accomplished in one of three ways: by witness/victim statements, by physical evidence, or by confession (Rossmo, 2009). The successful interviewing of suspects, victims, and witnesses is therefore of great importance. Until recently, no scientific knowledge was available to provide guidance for those responsible for conducting police interviews. This is particularly striking when it comes to sex offense perpetrators who are considered less likely to cooperate and confess during police interrogation. However, in the past two decades or so, some pioneering researchers started to empirically study this crucial topic in real world settings, in order to provide police interviewers with evidence-based advice and knowledge about victim, witness, and suspect interviewing in sex offense cases. This chapter reviews current empirical efforts in the field of investigative interviewing with suspects generally, and then focuses specifically on investigative interviewing with sex offense perpetrators.
... Those crimes should be linked with at least some degree of certainty to one offender. The geography of the crimes can actually be useful for linking crimes to a series (Deslauriers-Varin & Beauregard, 2014;Woodhams et al., 2019). ...
Solving sex crimes can be difficult. It is especially difficult to solve a sex offense case if there is no clear relationship between the victim and the offender. In those cases, one of the first questions that arises in the investigation is where to locate the offender. As many sex offenses that are committed by offenders with no clear link to the victim are outdoors, the geography of the crime might shed light on the case. Geographical offender profiling is an investigative method that can help police investigations to focus on areas where the offender most likely has an anchor point. A geographical offender profile is created by analyzing the geographical pattern of the crime(s) and the geographical behavior of the offender – the modus via – and his victim. This chapter provides an overview of the use of geography, and the geographical behavior of the victim and offender, to investigate sex offenses.
... One of the more parsimonious approaches to examining stability in chronic offending used a cross-tabulation method (Le Blanc & Kaspy, 1998) to compute whether chronic offending was present at two different age intervals. The introduction of a time component helped identify the dynamic nature of chronic offending that was masked by static measures that only looked at chronic offending over a single period of time (for a demonstration, see Deslauriers-Varin & Beauregard, 2014). Le Blanc and Kaspy's (1998) cross-tabulation method focused on the total volume of offending across just two different windows of measurement, making its investigation of the potentially dynamic nature of offending limited. ...
... Ainsi, les résultats de la présente étude pourraient être le fait d'un faible nombre d'agresseurs d'enfants qui emmènent leurs victimes dans les mêmes lieux extérieurs pour commettre leurs agressions puisque ces lieux sont relativement peu exposés et peu à risque. Des études précédentes portant sur la constance des comportements de délinquants sexuels et de leurs lieux choisis soutiennent en effet cette proposition (voir par exemple Deslauriers-Varin et Beauregard, 2013, 2014a, 2014bLundrigan, Czarnomski et Wilson, 2010 ;Santtila, Junkkila et Sandnabba, 2005). Les conclusions de ces travaux indiquent que les auteurs de crimes sexuels en série préfèrent choisir les mêmes lieux géographiques (centres commerciaux, quartiers, etc.) ou des lieux ayant des caractéristiques similaires. ...
Les études portant sur les crimes et les lieux ont toujours insisté sur l’importance de comprendre le profil spatial des crimes à l’aide d’unités d’analyse de plus en plus réduites. Même si de nombreuses études ont adopté cette perspective, peu se sont intéressées spécifiquement aux crimes à caractère sexuel. La présente étude se sert des données d’incidents enregistrés par la police pour étudier la distribution spatiale des infractions sexuelles ayant eu lieu entre le 1 er janvier 2016 et le 31 décembre 2018 à Austin, au Texas (N = 1381). Les infractions ont d’abord été divisées selon l’âge des victimes (enfant ou adulte) et le type d’acte sexuel perpétré (infraction sexuelle avec pénétration, avec contact et sans contact), ensuite trois mesures de concentration spatiale, des analyses de noyaux de densité et des analyses de dispersion spatiale ont été réalisées. Les résultats montrent que les infractions sexuelles commises contre des enfants et des adultes étaient concentrées dans l’espace, mais que leur degré de concentration dépendait du type d’acte commis. De plus, les analyses de dispersion spatiale semblent montrer que les segments de rue (et les intersections) où ont lieu de telles infractions diffèrent en fonction de la nature de l’acte sexuel perpétré. Les implications pour la prévention situationnelle et le maintien de l’ordre ( policing ) seront discutées.
... In fact, there are several studies that demonstrate that the variety of locations where these crimes generally take place are typically sites that are not considered by residential restriction laws. Indeed, Canadian studies have identified places that are more conducive to the commission of sex crimes, including shopping malls, bars, and victims' residences (Beauregard, Proulx, Rossmo, Leclerc, & Allaire, 2007;Deslauriers-Varin & Beauregard, 2010, 2014a, 2014b. It is also important to reiterate the fact that in a majority of sex offenses, the victim knows the offender prior to the abuse and the specific location may not matter that much from a prevention standpoint. ...
Uncertainty about sex offender treatment, the emergence of a risk-oriented correctional philosophy, and the rise of populist justice movements in reaction to violent sexual crimes and homicides involving children were the key ingredients favoring the emergence of new sex offender laws in the 1990s. This chapter focuses on the implementation of these laws, specifically, sex offender registries and public notification. The American, Canadian, and Australian experiences are examined and compared, with an emphasis on American public sex offender registry and notification laws, as these largely formed the basis for their implementation in other jurisdictions. The chapter presents the findings from more than 20 years of policy evaluation examining the impact of these legal dispositions. Research has shown that these dispositions are based on false and misguided assumptions about the characteristics of offenders and their risk of sexual reoffending. Additionally, policy evaluation research has highlighted that these dispositions are not effective crime prevention policies and their presence might create additional social problems not envisaged by those who promoted and implemented such laws. Finally, whereas the above policies are primarily reactive approaches to addressing the problem of sexual offending, this chapter also examines the impact of a more proactive, treatment-oriented approach.
... Ainsi, les résultats de la présente étude pourraient être le fait d'un faible nombre d'agresseurs d'enfants qui emmènent leurs victimes dans les mêmes lieux extérieurs pour commettre leurs agressions puisque ces lieux sont relativement peu exposés et peu à risque. Des études précédentes portant sur la constance des comportements de délinquants sexuels et de leurs lieux choisis soutiennent en effet cette proposition (voir par exemple Deslauriers-Varin et Beauregard, 2013, 2014a, 2014bLundrigan, Czarnomski et Wilson, 2010 ;Santtila, Junkkila et Sandnabba, 2005). Les conclusions de ces travaux indiquent que les auteurs de crimes sexuels en série préfèrent choisir les mêmes lieux géographiques (centres commerciaux, quartiers, etc.) ou des lieux ayant des caractéristiques similaires. ...
Les études portant sur les crimes et les lieux ont toujours insisté sur l’importance de comprendre le profil spatial des crimes à l’aide d’unités d’analyse de plus en plus réduites. Même si de nombreuses études ont adopté cette perspective, peu se sont intéressées spécifiquement aux crimes à caractère sexuel. La présente étude se sert des données d’incidents enregistrés par la police pour étudier la distribution spatiale des infractions sexuelles ayant eu lieu entre le 1er janvier 2016 et le 31 décembre 2018 à Austin, au Texas (N = 1381). Les infractions ont d’abord été divisées selon l’âge des victimes (enfant ou adulte) et le type d’acte sexuel perpétré (infraction sexuelle avec pénétration, avec contact et sans contact), ensuite trois mesures de concentration spatiale, des analyses de noyaux de densité et des analyses de dispersion spatiale ont été réalisées. Les résultats montrent que les infractions sexuelles commises contre des enfants et des adultes étaient concentrées dans l’espace, mais que leur degré de concentration dépendait du type d’acte commis. De plus, les analyses de dispersion spatiale semblent montrer que les segments de rue (et les intersections) où ont lieu de telles infractions diffèrent en fonction de la nature de l’acte sexuel perpétré. Les implications pour la prévention situationnelle et le maintien de l’ordre (policing) seront discutées.
The crime and place literature has consistently emphasized the importance of understanding spatial patterns of crime using increasingly smaller spatial units of analysis. Despite the growing number of studies that have used this perspective, very few of them have investigated sexual offences specifically. The current study uses police event data to investigate the spatial distribution of sexual offences that occurred between January 1, 2016 to December 31, 2018 in the city of Austin, Texas (N=1381). Disaggregating offences first by victim age (child versus adult) and then type of sexual act perpetrated (penetration, sexual contact, and sexual non-contact offences), three measures of spatial clustering, kernel density analyses, and a spatial point pattern test were used. Findings indicate that sexual offences perpetrated against children and adults were spatially concentrated, but the degree to which they clustered depended upon the type of sexual act committed. Furthermore, spatial point pattern findings suggested that the street segments (and intersections) affected by sexual crime differed according to the nature of the sexual act committed. Implications for situational crime prevention and policing are discussed.
... Criminological theoretical writings have long recognized the presence of much heterogeneity in offending and the presence of multiple patterns of criminal recidivism (e.g., Blokland & Lussier, 2015;Deslauriers-Varin, & Beauregard, 2014) and various approaches and analytical strategies have been proposed in the scientific literature to disaggregate individual profiles as well as offending patterns for risk prediction purposes (e.g., Steadman et al., 2000). Among these analytical strategies and methods, a branch of machine learning statistical techniques has led researchers to explore the use and examine the benefits of decision tree algorithms (DTA). ...
... Since the time of Grubin et al.'s study, the number of empirical studies examining behavioral crime linkage analysis in cases of sexual violence has grown (e.g., Bennell et al., 2009;Deslauriers-Varin, & Beauregard, 2014a;Harbers, Deslauriers-Varin, Beauregard, & van der Kemp, 2012;Slater, Woodhams, & Hamilton-Giachritsis, 2015;Woodhams, Grant, & Price, 2007). Generally speaking, this research suggests that it may be possible to use behavioral evidence to link such crimes (Bennell, Mugford, Ellingwood, & Woodhams, 2014). ...
Sexual assault and abuse are among the most heinous crimes that can be committed. However, these crimes are largely underreported worldwide. Despite this, research on the investigation of sexual assault and abuse cases has been slow to emerge and there exists an important gap between the current knowledge on sexual victimization and the police response to it. Research is required on many topics related to the investigation of sexual assault and abuse, including research that can improve the effectiveness of investigative interviews and the accurate identification and prioritization of suspects. The goal of the current chapter is to review current research efforts in these two areas –investigative interviewing and suspect identification and prioritization procedures – and to discuss some of the challenges associated with these tasks , and the investigation of sexual assault and abuse more generally (e.g., false allegations, false confessions, cognitive biases).
... Based on official records, offenders had committed an average of 2.91 (SD = 6.34) violent sexual offenses, 1.00 non-violent sexual offenses (SD = 3.08), 2.46 violent non-sexual offenses (SD = 4.40), and 11.99 non-sexual nonviolent offenses (SD = 19.60). The offenders included in the present study have been included in previous studies that addressed distinct research questions (e.g., Beauregard et al., 2012;Deslauriers-Varin, & Beauregard, 2014;Goodwill, Lehmann, Beauregard, & Andrei, 2016;Ha & Beauregard, 2016;Hewitt & Beauregard, 2014b;Reid & Beauregard, 2017). ...
Purpose: Victim age polymorphism (also referred to as victim age crossover) describes sexual offenders who offend against multiple age groups. The present study examined whether polymorphic offenders could be differentiated from age-specific offenders based on the role of opportunity in the commission of their offenses.
Methods: The current study examined age polymorphism in 72 sexual offenders who committed 361 stranger offenses. Incarcerated offenders were interviewed about their sexual offending history and provided information on their crime scene behaviors (i.e., pre-crime activities, victim selection, and behaviors during the commission of the offense, such as sexual behaviors), which was cross-checked with file information. A PCA and logistic regression were conducted using crime scene behaviors to determine latent constructs that differentiated age-specific and age polymorphic offenders. Individual crime scene behaviors were also analyzed.
Results: Polymorphism occurred in 36% of offenders' sexual offense histories with most polymorphic offenders victimizing those aged 11 to 14 and at least one other age group. Compared to age-specific offenders, polymorphic offenders were more opportunistic and less concerned with the specific characteristics of their victim.
Conclusion: Polymorphic offenders can be distinguished from age-specific offenders by their pre-crime decisions and the sexual behaviors committed during the offense.
... These findings suggest that SHOs do not specialize in sexual crimes and are generally involved in other crimes, especially those involving violence (i.e., non-sexual violent crimes). This is consonant with criminal career research generally that reveals some evidence of specialization (Armstrong & Britt, 2004;Deslauriers-Varin & Beauregard, 2014 ;Jennings, Zgoba, Donner, Henderson, & Tewksbury, 2014;Reid, Beauregard, Fedina, & Frith, 2014;Tillyer, Tillyer, & Kelsay, 2015) couched within a broader behavioral pattern of versatile antisocial behaviors (Britt, 1994;DeLisi, 2001DeLisi, , 2014DeLisi & Piquero, 2011;DeLisi & Scherer, 2006;Gottfredson & Hirschi, 1990;Kaseweter, Woodworth, Logan, & Freimuth, 2016). Even among sexual offenders, there is evidence for both specialized and versatile offending (Blokland & Lussier, 2015;Cale, Lussier, McCuish, & Corrado, 2015;Harris, Smallbone, Dennison, & Knight, 2009;Soothill, Francis, Sanderson, & Ackerley, 2000). ...
Sexual murderers perpetrate homicide and rape/sexual abuse, but it is unclear whether they should primarily be considered homicide offenders, sexual offenders, or both. Most studies have merged together different types of non-homicidal sex offenders (NHSOs), neglecting to consider the potential differences between the nonviolent and violent sex offenders. Here, we suggest it is important to isolate those violent sex offenders who inflict severe physical injuries that could potentially lead to a lethal outcome. Therefore, the aim of the current study is to compare different measures of the criminal career on three groups of sex offenders: NHSOs, violent NHSOs, and sexual homicide offenders (SHOs) using data from 616 incarcerated male sex offenders in a Federal penitentiary in Canada. Interestingly, the group of sex offenders with the worst criminal career profile was not the SHOs, but the violent NHSOs. Violent NHSOs had the greatest number of prior convictions and the most varied and versatile criminal career. Therefore, we suggest that based on their criminal career, SHOs should be considered more as murderers than sex offenders. However, to fully answer this question, future studies should include a group of non-sexual homicide offenders.
... Sexual offending and crime site selection. Deslauriers-Varin and Beauregard (2014) used latent class analysis to investigate the stability of crime sites used by serial sex offenders based on environmental choices. They analyzed information from 361 sex offences, committed by 72 serial sex offenders. ...
The present study sought to replicate existing research in order to evaluate the similarities between distinct samples of sexual offenders. The research also sought to use a more advanced statistical procedure than previous research to derive a typology and see how it fit within the framework of existing literature. Data were gathered from 106 pre-sentence reports assessing adult male sexual offenders. Prior research examining typologies of adolescent male sexual offenders and adult female sexual offenders were replicated and compared to the collected data. Some similarities between the adolescent male and adult male sexual offenders were found, such as a relationship between type of offender and recidivism risk. The adult female and adult male sexual offenders had a differing number of sub-types, but offender age and victim age differentiated between the groups for both samples. Following replication, latent class analysis was used to uncover naturally occurring groups in the collected data using offender and offence characteristics. The analyses revealed five classes of offenders, which were labelled Mixed Victim Assaulters, Non-Pedophilic Mixed Gender Offenders, Preferential Pedophiles, Non-Aggressive Incest Offenders, and Non-Aggressive Non-Pedophilic Child Molesters. Of the eight variables selected for the analyses, the classes varied mainly in the areas of presence of pedophilia, presence of a substance/alcohol disorder, use of aggression, victim gender, victim age, and victim relationship. Sexual victimization history and offender age did not provide much class differentiation. External analyses revealed that among the classes, ethnicity, presence of a mood/anxiety disorder, and presence of a personality disorder differed. The classes involving child-oriented offences supported existing typologies in the literature, whereas the class involving adult-oriented offences did not align with existing typologies. A typology rooted in empirical findings, such as the typology developed for this research, can provide significant insight into the heterogeneous nature of those who commit sexual offences. This insight can allow researchers and clinicians to best assess, treat, and reintegrate sexual offenders, as the offenders may require different preventive techniques and have different treatment needs based on their class characteristics.
... Furthermore, even among persistent offenders, also referred to as serial or repeat sexual aggressors of women, research has shown much heterogeneity in their offending patterns (e.g., Miethe, Olson, & Mitchell, 2006). Indeed, there are serial sexual aggressors who sexually offend over long time periods in line with a propensity approach, but even then, their offending remains relatively intermittent, characterized by a succession of brief offending periods followed by long non-offending periods that theories of sexual aggression do not address (Deslauriers-Varin & Beauregard, 2014). In other words, even among persistent offenders, sexual aggression remains relatively inconsistent and intermittent. ...
Several explanations have been proposed to explain the origins and the development of rape and sexual aggression against women. For the most part, the first three generations of research and theorizing provided an inherently static view of the propensity among males to commit a sexual aggression, providing little information about the developmental processes involved in the origins and course of sexually aggressive behavior. This article provides a review of contemporary explanations of sexual aggression against women and an examination of the underlying developmental issues that these models imply. Given the emergence of longitudinal research on sexual aggression, these issues are then contrasted and compared with the relatively nascent body of knowledge about the origins and the development of sexual aggression over the life course. More specifically, in recent years a fourth generation of research and theorizing concerned by the developmental and life course factors conducive to rape and sexual aggression has emerged. This fourth generation proposes a more dynamic etiological framework to understand the origins and the development of sexually aggressive behaviors that is directed by men toward women. Emerging research from this generation highlight unresolved issues about, among other things, the understanding of the continuity and discontinuity of rape and sexual aggression over time as well as the developmental pathways leading to rape and sexual aggression.
... 6 To date, no studies have examined the prevalence of chronic sexual offending and whether chronic JSO present a clinical profile distinct from other nonchronic JSO. The frequency of sexual offending examined in past research does not take into consideration the time at risk or how long offenders were active, or as criminologists call it, the lambda (i.e., offending rate; see Deslauriers- Varin & Beauregard, 2014). ...
Until recently, developmental criminologists have remained relatively silent about the issue of juvenile sex offending. Consequently, concepts and knowledge from the field developmental criminology are relatively unknown to researchers and practitioners working in the area of juvenile sex offending. In fact, for the past two or three decades, concepts and knowledge derived from clinical studies conducted with samples of adult sex offenders have been imported to guide the explanation and prevention of juvenile sex offending. This trend has led many to believe that today’s juvenile sex offenders are tomorrow’s adult sex offenders. This chapter builds on the research framework proposed by Dr. Marc LeBlanc by reviewing the state of knowledge on the development of juvenile sex offending. Developmental concepts are defined and proposed to organize findings of past research but also to stimulate and guide future prospective longitudinal studies aiming to describe, explain, and predict the development of juvenile sex offending.
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.
The crime and place literature has consistently emphasized the importance of understanding spatial patterns of crime using increasingly smaller spatial units of analysis. Despite the growing number of studies that have used this perspective, very few of them have investigated sexual offenses specifically. The current study uses police event data to investigate the spatial distribution of sexual offenses that occurred between January 1, 2016 and December 31, 2018 in Austin, Texas (N = 1381). Disaggregating offenses first by victim age (child versus adult) and then type of sexual act perpetrated (penetration, sexual contact, and sexual non-contact offenses), three measures of spatial clustering, kernel density analyses, and a spatial point pattern test are used. Findings indicate that sexual offenses perpetrated against children and adults are spatially concentrated, but the degree to which they cluster depends upon the type of sexual act committed. Furthermore, within each of these victim profiles, spatial point pattern findings suggest that the street segments (and intersections) affected by sexual crime differ according to the nature of the sexual act committed. Implications for situational crime prevention and policing are discussed.
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.
The present study examined whether there are different processes operating in the crime location choices between body‐disposing and non‐body‐disposing serial killers and between sexual serial killers and acquisitive serial killers. A sample of 49 series of solved German serial killings is used to examine the differences in travelled distances between these groups of killers. Nonparametric tests revealed that body‐disposing and non‐body‐disposing serial killers and sexual and acquisitive serial killers did not constitute subgroups of serial killers regarding their spatial behaviour. The results suggest that the compared groups are subjected to the same factors that influence their travelled distances. Furthermore, the possible role of planning and anticipated emotions in crime location choices of serial killers is discussed, as well as the limitations of the study and recommendations for future research.
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).
Current American policies and responses to juvenile sex offending have been criticized for being based on myths, misconceptions, and unsubstantiated claims. In spite of the criticism, no organizing framework has been proposed to guide policy development with respect to the prevention of juvenile sex offending. This article proposes a developmental life course (DLC) criminology perspective to investigate the origins, development, and termination of sex offending among youth. It also provides a review of the current state of knowledge regarding various parameters characterizing the development of sex offending (e.g., prevalence, age of onset, frequency, persistence, continuity in adulthood, and versatility). The review highlights some heterogeneity across these developmental parameters suggesting the presence of different sex offending patterns among youth. In fact, it is proposed that, based on the current knowledge, such heterogeneity can be accounted for by a dual taxonomy of adolescents involved in sexual offenses: (a) the adolescent-limited and (b) the high-rate/slow-desister. The DLC criminology approach and the dual taxonomy are proposed as organizing frameworks to conduct prospective longitudinal research to better understand the origins and development of sex offending and to guide policy development and responses to at-risk youth and those who have committed sexual offenses.
© The Author(s) 2015.
PurposeContinued debate surrounds whether or not offender profiling is a valid practice. Critics have mainly contended that few studies have produced clear, quantifiable, evidence of a link between crime scene actions (A) and offender characteristics (C). Arguing that this is due to a failure to study offender actions as part of a dynamic decision-making process, this study sought to identify action phases that are representative of the general decisions an offender must make during the commission of a sexual offence, and relate these decisions to known characteristics of the offender (C).Methods
Two-step cluster analyses were performed on data from 347 stranger sexual offences, committed by 69 serial sexual offenders, by action phase: (1) search; (2) selection; (3) approach; (4) assault; and also for an offender's (5) characteristics. Multiple correspondence analysis (MCA) was then utilized to investigate the inter-relationship of action phase clusters and offender characteristics.ResultsThe MCA results indicated that specific behavioural macro-clusters formed across the various actions phase and offender characteristic clusters in a meaningful way. Additionally, the macro-clusters themselves corresponded to the extant literature on sexual assault, revealing several points of congruence between offender crime scene actions and offender characteristics.Conclusion
The results of the study demonstrate that when crime scene behaviours are interpreted within a dynamic decision-making process (i.e., utilizing action phases), reliable and valid empirical links may potentially be drawn between an offenders behavioural actions and their characteristics.
We present a criminal careers typology of child sexual abusers constructed in terms of their offending persistence (persistent vs. limited) and versatility (specialized vs. versatile). Analyses were conducted on the official records of 362 convicted offenders, 213 of whom also provided confidential self-report data on their personal and offending histories. Forty-one percent of the sample were currently serving sentences for their first sexual offense conviction(s) but had at least one prior conviction for a nonsexual offense (limited/versatile); 36.4% had no previous convictions of any kind (limited/specialized); 17.8% had prior convictions for sexual and nonsexual offenses (persistent/versatile); and 4.8% had prior convictions for sexual offenses only (persistent/specialized). These four groups differed on a range of personal and offense-related variables, including abuse histories, sexual orientation, age at first sexual contact with a child, number of victims, duration of sexual involvement with victims, victim gender, and whether victims were familial or nonfamilial. These differences suggest the need to adopt different treatment and prevention strategies that target the specific characteristics of each group.
In the absence of forensic evidence (such as DNA or fingerprints), offender behavior can be used to identify crimes that have been committed by the same person (referred to as behavioral case linkage). The current study presents the first empirical test of whether it is possible to link different types of crime using simple aspects of offender behavior. The discrimination accuracy of the kilometer distance between offense locations (the intercrime distance) and the number of days between offenses (temporal proximity) was examined across a range of crimes, including violent, sexual, and property-related offenses. Both the intercrime distance and temporal proximity were able to achieve statistically significant levels of discrimination accuracy that were comparable across and within crime types and categories. The theoretical and practical implications of these findings are discussed and recommendations made for future research.
Much of the knowledge base on offense specialization indicates that, although there is some (short-term) specialization, it exists amidst much versatility in offending. Yet this general conclusion is drawn on studies using very different conceptualizations of specialization and emerges with data primarily through the first two to three decades of life. Using data on a sample of Dutch offenders through age 72 years, this article introduces and applies a new method for studying individual offender specialization over the life course. The results indicate that although, in general, individual offending patterns over the life course are diverse, there is also evidence of an age—diversity curve. Linking offense frequency trajectories to the estimated diversity index, the authors also examine distinct specialization patterns across unique trajectory groups. Implications for theory and research are outlined.
Burglary victimization is associated with a temporary elevated risk of future victimization for the same property and nearby properties. Previous research suggests that often the initial and subsequent burglaries involve the same offenders. This paper tests this assertion, using data on detected residential burglaries during the period 1996—2004 in The Hague and its environs, in the Netherlands. It demonstrates that pairs of detected burglaries occurring in close proximity in space and time are much more likely to involve the same offenders than pairs that are not so related. Topics for future research and implications for the detection of burglaries are addressed.
Policies aimed at managing high-risk offenders, which include sex offenders, often assume they are a homogeneous population. These policies also tend to assume the pattern of offending is the same for all sex offenders, and is stable. This study challenges these assumptions by examining the life course offending trajectories of 780 convicted adult male sexual offenders. The men were referred to the Massachusetts Treatment Center for civil commitment between 1959 and 1984. The changing number of both sexual and any offenses were examined by age using Group-Based Trajectory Modeling. We identified a four-trajectory model for all offending and a four-trajectory model for sexual offending. The identified groups varied in several offending patterns including criminal onset, length of criminal careers, age of peak offending, and time of entry into the treatment center. Late adult onset of sex offending was found to be associated with child molestation, whereas early-onset trajectories were associated with rape. Implications for future research and policy are discussed.
Several theoretical traditions offer insights into individual
success in conventional activities. We extend this work, suggesting
that explanations of success also apply to crime: although prosperity
in licit or illicit activities has several unique antecedents, success
in either endeavor is influenced by common faactors. Most research on
conventional success focuses on the effects of human and social capital,
and criminal forms of these are important for illegal success. We argue
that various aspects of conventional personal capital -- a heightened
desire for wealth, a propensity for risk-taking, a willingness to
cooperate and competence -- also play important roles in both legal and
illegal prosperity. We demonstrate the importance of various types of
capital, particularly the salience of personal capital, with data on
drug-selling income.
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.
Purpose. Through an examination of serial rape data, the current article presents arguments supporting the use of receiver operating characteristic (ROC) analysis over traditional methods in addressing challenges that arise when attempting to link serial crimes. Primarily, these arguments centre on the fact that traditional linking methods do not take into account how linking accuracy will vary as a function of the threshold used for determining when two crimes are similar enough to be considered linked.
Methods. Considered for analysis were 27 crime scene behaviours exhibited in 126 rapes, which were committed by 42 perpetrators. Similarity scores were derived for every possible crime pair in the sample. These measures of similarity were then subjected to ROC analysis in order to (1) determine threshold‐independent measures of linking accuracy and (2) set appropriate decision thresholds for linking purposes.
Results. By providing a measure of linking accuracy that is not biased by threshold placement, the analysis confirmed that it is possible to link crimes at a level that significantly exceeds chance ( AUC = .75). The use of ROC analysis also allowed for the identification of decision thresholds that resulted in the desired balance between various linking outcomes (e.g. hits and false alarms).
Conclusions. ROC analysis is exclusive in its ability to circumvent the limitations of threshold‐specific results yielded from traditional approaches to linkage analysis. Moreover, results of the current analysis provide a basis for challenging common assumptions underlying the linking task.
Whether criminals are specialized or versatile in their offending is a long-standing research area that has been recently
revitalized by a paradigm that recognizes that both specialization and versatility characterize offending careers. Based on
data from an enriched sample of 500 adult habitual criminals, the current study introduces a measure of relative specialization—the
offense specialization coefficient—and a novel analytical technique called simultaneous quantile regression to further the
study of specialization. Although offenders committed a mix of offenses, there was considerable and at times pronounced evidence
of specialization. Age, sex, and arrest onset had differential predictive validity of specialization for eight crimes at the
75th and 95th quantiles. Implications and suggestions for future research are offered.
KeywordsSpecialization–Versatility–Criminal careers–Career criminal–Typologies
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
Common error in bibliographies: "Étude comparative de la distribution florale dans une portion des Alpes et des Jura".
Serial rapists have the propensity to cause harm to a significant number of victims, meaning that they are of concern to the police as well as to treatment providers. Despite the serious nature of their offending, there are surprisingly few studies that provide information regarding their characteristics, the types of victim they target, or the nature of the sexual offenses they commit, and those studies that do exist are varied in their findings. This study provides a descriptive analysis of serial rape in South Africa. One hundred and nineteen sexual offenses committed by 22 serial rapists were sampled. Information regarding the victims, the offenders, and the crimes they had committed were extracted from police files. The characteristics of victims and offenders are reported as well as the frequencies for 114 different crime scene behaviors. When compared with samples of serial sex offenders from other countries, differences emerged in victim characteristics and crime scene behaviors, including how the victims were targeted, the sexual behaviors engaged in, and the incidence of physical violence. The implications of these observed differences for practice are discussed.
This study investigates target selection scripts of 72 serial sex offenders who have committed a total of 361 sex crimes on stranger victims. Using latent class analysis, three target selection scripts were identified based on the victim's activities prior to the crime, each presenting two different tracks: (1) the Home script, which includes the (a) intrusion track and the (b) invited track, (2) the Outdoor script, which includes the (a) noncoercive track and the (b) coercive track, and (3) the Social script, which includes the (a) onsite track and the (b) off-site track. The scripts identified appeared to be used by both sexual aggressors of children and sexual aggressors of adults. In addition, a high proportion of crime switching was found among the identified scripts, with half of the 72 offenders switching scripts at least once. The theoretical relevance of these target selection scripts and their practical implications for situational crime prevention strategies are discussed.
Criminal careers have long occupied the imaginations of criminologists. Since the 1986 publication of the National Academy of Sciences report on criminal careers and career criminals, a variety of theoretical, empirical, and policy issues have surfaced. Data on key criminal career dimensions of prevalence, frequency, specialization, and desistance have raised theoretical questions regarding the patterning of criminal activity over the life course. Recent research has identified important methodological issues, including the relationship between past and future criminal activity, and potential explanations for this relationship: state dependence and persistent heterogeneity. Advanced statistical techniques have been developed to address these challenges. Criminal career research has identified important policy issues such as individual prediction of offending frequency and career duration, and has shifted the focus toward the interplay between risk and protective factors.
This article analyzes how street robbers decide on where to attack their victims. Using data on nearly 13,000 robberies, on
the approximately 18,000 offenders involved in these robberies, and on the nearly 25,000 census blocks in the city of Chicago,
we utilize the discrete choice framework to assess which criteria motivate the location decisions of street robbers. We demonstrate
that they attack near their own homes, on easily accessible blocks, where legal and illegal cash economies are present, and
that these effects spill over to adjacent blocks.
Purpose
The study examines whether the use of forensic awareness strategies increases the chance of avoiding police detection in sexual homicide.
Methods
Logistic and negative binomial regression analyses are used on a sample of 350 cases of sexual homicide – 250 solved and 100 unsolved cases – in order to determine if forensic awareness strategies are related to the status of the case (i.e., solved versus unsolved) and the number of days before body recovery, while controlling for certain victim characteristics.
Results
Although an offender’s use of precautions does not seem to increase the offender’s chance of avoiding police detection, some modus operandi behavior adopted by the offender at the crime scene may help to delay the discovery of the victim, and thus delay the offender’s apprehension. Moreover, the likelihood of whether or not a sexual murderer is apprehended varied significantly across victim characteristics.
Conclusion
Some offenders seem to exhibit rational thinking in targeting certain types of victims and in adopting certain strategies in order to delay body recovery. Number of days until body recovery is a more appropriate measure of detection avoidance than case status, as it is not biased by administrative rules or timing of data entry.
The present study examines consistency of crime behaviour among 347 sexual assaults committed by 69 serial sex offenders. This individual behaviour approach—the so-called signature approach—reveals which features of crime behaviour are consistent across a series and which features are not. The consistency scores were calculated using the Jaccard's coefficient. The results of this study indicate that there are some crime features of a serial sexual assault that can be useful for the purpose of linkage. Another important finding is that consistency scores for different variables within the same category can differ substantially. Moreover, serial sex offenders are more likely to be consistent in their environmental crime features when they are also consistent in their behavioural features, and vice versa. Serial sex offenders are also more likely to be consistent in the behavioural features of their assaults as the crime series gets longer. The implications of the results are discussed in relation to both research and practise
This study presents a new approach to developing a typology of criminal activity. The distinguishing feature of the analysis is that it concentrates on determining types of activity rather than the amounts of activity over the life course. The methodology involves investigating criminal activity in a succession of five-year periods rather than the conventional approach of summarizing a ‘lifetime’ of crime. This provides scope for assessing changes and pathways of criminal activity as offenders grow older, and gives new insight into the concepts of specialization and versatility. The Home Office Offenders Index birth cohort for 1953 provided official conviction histories up to 1993 (age 40), and latent class analysis identified a fixed number of types of criminal behaviour separately for males and females. The patterns of offending varied markedly between males and females. Male offending (with nine identified types) showed greater diversity than female offending (with three identified types). For the males, each type of offending had a distinct age profile, but this was not evident with the females. A new definition of offending specialization is given, and is shown to increase for males as offenders grow older. A case study on one of the male offending types illustrates the potential for identifying pathways of crime.
Crime linkage analysis constitutes a tool to help investigators prioritize suspects, but a scarcity of research and methodological issues limits our knowledge on behavioral consistency in sexual offenses. The current study identifies geographic and environmental factors that are useful in examining offending consistency across series of sexual assaults using different specialization coefficients. The current study draws on criminal career research and methodology as a way to improve the study of behavioral consistency. The sample includes 72 serial stranger sex offenders who have committed a total of 361 sexual assaults. Three methods are used (i.e., diversity index, forward specialization coefficient, and Jaccard’s coefficient) and reveal a high degree of offending consistency. All three methods also highlight promising factors to rely on for crime linkage of serial sexual offenses. Empirical and methodological implications for behavioral consistency research are discussed as well as practical implications for police investigations and crime linkage.
This paper discusses the development of a filter model for prioritizing possible links in dwelling burglary. The filters utilize the central aspects of crime scene information that is available and accessible to investigators in burglary, namely geo-spatial, temporal, behavioural, and dwelling information. The proposed filters were analysed using a sample of 215 dwelling burglaries committed by 43 serial burglars (i.e. 5 offences each) in order to determine the sequence in which the filters should be considered in prioritizing possible linked offences. The results indicated that the following order (i.e. better performance to worse performance) was most effective at linking offences, utilizing: (1) geo-spatial information, (2) temporal aspects, (3) behavioural information and, lastly, (4) dwelling characteristics. Specifically, the results indicated that offences in close proximity to one another should be given priority. Further, any offence occurring within a 28-day span before or after the index offence should be given priority. The paper argues that behavioural and dwelling characteristics are less effective for linking than geo-spatial and temporal information because the former two aspects are influenced significantly by situational and contextual cues on offender decision-making.
Purpose: The current study examines significant variations in criminal achievement across sex offenders. To examine the "successful" sex offender, the study proposes a concept of achievement in sexual offending defined as the ability to maximise the payoffs of a crime opportunity while minimizing the costs. Methods: The study is based on a sample of convicted adult male sex offenders using retrospective longitudinal data. Results: The study findings show a wide variation in criminal achievement, a variation that is not correlated with the severity of sentences meted out or the actuarial risk scores obtained by these offenders. Those offenders who specialize in sex crimes were shown to be the most productive and least detected offenders. Two types of successful offenders emerge, the first relying on his conventional background in targeting a victim that can be repeatedly abused for a long period without detection. The second is a younger offender that is successful in the sense of being able to complete aggressions on multiple victims. Conclusions: Results suggest that the successful sex offender is not "detected" once he enters the criminal justice system, nor is he handled in a way that may deter him from sexually reoffending in the future.
The life-course approach to criminal career research has devoted a good deal of attention to the generality or specialization of offending behavior. Typically, extant research demonstrates versatility on the part of offenders, yet such findings could be attributable, at least in part, to time and measurement aggregation bias. This work uses a temporally disaggregated and individualized measure of diversity in offending to determine whether the previous findings of generality hold up to shifts in methodology. Using data from a sample of serious felons, results indicated that the magnitude of specialization is greater than in prior studies. Regression results indicated that certain demographic and local life-circumstance variables are related to the extent of diversity. Theoretical and methodological implications are identified and discussed.
Sexual offending is on the political agenda but there has been little research focus on the four offence categories-indecent assault against a female, indecent assault against a male, indecency between males and unlawful sexual intercourse with a girl under 16-which together comprise the vast majority of convictions for sexual offences in England and Wales. We consider the criminal record (1963-94 inclusive) of the 6,097 males convicted of one of these offences in 1973. The results are discussed in terms of criminality, heterogeneity, dangerousness and specialization. By recognizing two levels of analysis-general crime level and sex crime level-we argue that sex offenders can be both generalists and specialists; they may range widely across a spectrum of offences but still specialize within sexual offending.
This paper outlines a brief history of the evolutionary trajectory of offender profiling and illustrates the three broad strands (investigative, clinical, and statistical) that emerged in the 1970s–1990s. We then indicate how a more pragmatic, interdisciplinary practitioner–academic model has emerged in recent years and go on to describe the range of contributions that are now made across the criminal justice field. More recently termed ‘behavioural investigative advice’ in the UK, the paper then argues that whilst a range of potential contributions exist (from linking crimes, risk assessment, provision of bad character evidence, investigative interviewing advice, to geoprofiling), the nature of the process by which that contribution occurs is not yet well understood. The review of these potential contributions concludes with several suggestions and recommendations for further research and relevant methodologies by which to conduct that research. This includes the requirement to combine conceptual and theory-driven models alongside empirically driven statistical approaches, as well as the requirement to more precisely delineate and describe how contributions are made by behavioural experts through cognitive task analyses and associated methods.
The concept of “fixed emotional propensity” was explored by evaluating 62 sexual offenses committed by 23 male repeat offenders. Two general clusters of sex offenders were discerned, that is, more aggressive versus less aggressive offenders. In addition, sexual offenses committed by the same offender were much more similar than those committed by different offenders. The more similar the offense pattern, the greater the number of alleged offenses. In general, the results indicated that fixed emotional propensity is a useful concept in forensic evaluation.
In the absence of physical evidence, investigators must often rely on offence behaviours when determining whether several crimes are linked to a common offender. A variety of factors can potentially influence the degree to which accurate linking is possible, including the similarity coefficient used to assess across-crime similarity. The current study examines the performance of two similarity coefficients that have recently been compared to one another, Jaccard's coefficient (J) and the taxonomic similarity index (Δs), using samples of two crime types, serial homicide (N=237) and serial burglary (N=210). In contrast to previous research, the results indicate that Δs does not significantly outperform J with respect to linking accuracy. In addition, both coefficients lead to higher levels of linking accuracy in cases of serial homicide compared to serial burglary. Potential explanations for these findings are presented and their implications are discussed.
Challenges one of Western culture's most deeply held assumptions: that violence against women is different from violence against men. The author argues that this type of violence is rarely the result of sexism or hatred against women. He cites research suggesting that the motives for violence against women are similar to the motives for violence against men: to gain control or retribution and to promote or defend self-image. The motives play a role in almost all violence, regardless of gender. Using a comparative method to determine how violence against women differs from violence against men, the author illustrates not only that violence against women is less frequent than violence against men but also that our culture and legal system treat it more harshly. Contrary to the claims that the courts "blame the vistim" in cases of violence against women, the author shows that the tradition of protection of women sometimes produces the opposite affect and that it is due process and not sexism that makes, for instance, rape cases seem biased against women. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
One of the most problematic aspects of predatory violent crime is the volume of tips and suspects generated through their investigation. Traditional police methods are not always sufficient and detectives need alternative tactics to assist them in these types of cases. Geographic profiling, a strategic information management system designed to support investigative efforts in cases of serial murder, rape and arson, is one such approach. Other topics discussed include: introduction; investigative difficulties; geographic profiling; and conclusion. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
This study examines the crime patterns of 76 New Zealand serial sexual offenders in order to determine the extent to which offenders display locational consistency in their choice of crime locations. More specifically, the hypothesis was that there would be intraseries consistency in the distances travelled (spatial consistency) and the characteristics of the crime sites selected (environmental consistency) by serial sexual offenders.
For spatial consistency to be tested, the distances travelled from home to offend and the criminal range for each offence series were analysed. Support was found for spatial consistency, and, in line with much overseas research, it was also found that the offenders typically did not travel very far from home to offend (median distance of 3 km).
The environmental consistency measure was made up of various physical, temporal, and contextual variables that described the environmental characteristics of an offence. As hypothesised, it was found that offenders displayed intraseries environmental consistency in offence site selection beyond the level of that expected by chance. The implications of this both for understanding offender spatial decision making and for geographical profiling are discussed. Copyright
This study examines the criminal arrest records of a Danish birth cohort of 28,884 men to test the hypothesis that specialization exists for violent offending. Property offending is included for comparison. Specialization in violence is found to exist for offenders with more than three arrests, and specialization in property offending, for offenders with fewer than four arrests. Knowledge of past violent offending is discussed as a potentially valuable part of the predictive equation of future violence.
As we have tried to explain in this paper, we believe that the concept of a criminal career, the distinction between participation and frequency, and the longitudinal research method all have considerable value for criminological theory and policy. We have no particular stake in demonstrating that the individual frequency of offending stays constant over age; however, based on the present state of knowledge, it appears that participation in offending, but not frequency, varies with age. We are not uncritical enthusiasts of the concepts of career criminals and selective incapacitation, but we do believe that these policy ideas can stimulate important research. The outcome of the debate over these policies, however, has little relevance for the value of research on criminal careers, the participation/frequency distinction, and the longitudinal method - all of which rest on theoretical, methodological, and other scholarly considerations.
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.
Many offenses take place close to where the offender lives. Anecdotal evidence suggests that offenders also might commit crimes near their former homes. Building on crime pattern theory and combining information from police records and other sources, this study confirms that offenders who commit robberies, residential burglaries, thefts from vehicles, and assaults are more likely to target their current and former residential areas than similar areas they never lived in. In support of the argument that spatial awareness mediates the effects of past and current residence, it also is shown that areas of past and present residence are more likely to be targeted if the offender lived in the area for a long time instead of briefly and if the offender has moved away from the area only recently rather than a long time ago. The theoretical implications of these findings and their use for investigative purposes are discussed, and suggestions for future inquiry are made.
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.
Whilst case linkage is used with serious forms of serial crime (e.g. rape and murder), the potential exists for it to be used with volume crime. This study replicates and extends previous research on the behavioural linking of burglaries. One hundred and sixty solved residential burglaries were sampled from a British police force. From these, 80 linked crime pairs (committed by the same serial offender) and 80 unlinked crime pairs (committed by two different serial offenders) were created. Following the methodology used by previous researchers, the behavioural similarity, geographical proximity, and temporal proximity of linked crime pairs were compared with those of unlinked crime pairs. Geographical and temporal proximity possessed a high degree of predictive accuracy in distinguishing linked from unlinked pairs as assessed by logistic regression and receiver operating characteristic analyses. Comparatively, other traditional modus operandi behaviours showed less potential for linkage. Whilst personality psychology literature has suggested we might expect to find a relationship between temporal proximity and behavioural consistency, such a relationship was not observed. Copyright © 2010 John Wiley & Sons, Ltd.
Purpose. The psychological hypotheses that form the foundations for ‘Offender Profiling’ are identified and the research that has tested them is reviewed. Argument. ‘Offender profiling’ is taken to be the derivation of inferences about acriminal from aspects of the crime(s) he or she has committed. For this process to move beyond deduction based on personal opinion and anecdote to an empirically based science, a number of aspects of criminal activity need to be distinguished and examined. The notion of a hierarchy of criminal differentiation is introduced to highlight the need to search for consistencies and variations at many levels of that hierarchy. However, current research indicates that the key distinctions are those that differentiate, within classes of crime, between offences and between offenders. This also leads to the hypothesis ofa circular ordering of criminal actions, analogous to the colour circle, a ‘radex’. The radex model, tested using Multi-Dimensional Scaling (MDS) procedures, allows specific hypotheses to be developed about important constituents of criminal differentiation: Salience. MDS analyses reveal the importance of the frequency of criminal actions as the basis on which the significance of those actions can be established. Models of differentiation. The research reviewed mainly supports distinctions between criminals in terms of the forms of their transactions with their explicit or implicit victims. Consistency. Offenders have been shown to exhibit similar patterns of action on different occasions. The most reliable examples of this currently are in studies of the spatial behaviour of criminals. Inference. Under limited conditions it is possible to show associations between the characteristics of offenders and the thematic focus of their crimes. In general these results provide support for models of thematic consistency that link the dominant themes in an offender's crimes to characteristic aspects of his or her lifestyle and offending history. Implications. Much of what passes for ‘offender profiling’ in practice and as reported in the factual and fictional media has no basis in empirical research. However, there are some promising results emerging in some areas of study. These results are most likely to be of value to police investigations when incorporated into decision support systems and the training of police officers. The results doalso provide new insights into the psychology o crime.
This paper focuses on the characterization of the criminal careers of youthful offenders. It was found that these criminal careers could be modeled with parameters rejecting constant individual rates of offending and constant probability of career termination; population heterogeneity could be adequately represented by two distinct groups—designated here as “frequents” and occasionals.” These parameters were estimated for the multiple offenders in a London cohort studied from their first convictions until age 25. In that cohort, the frequents were estimated to have an annual conviction rate of 1.14 convictions per year (constant with age) and a probability of career termination of .10 following each conviction; the occasionals had an annual conviction rate of .41 and termination probability of .33 following each conviction; the frequents were estimated to comprise 43% of the population, and the occasionals the others 57%. While this parsimonious model structure was adequate for the London cohort, it must still be tested with other offender populations.
A rational choice theory approach was used to analyze the offense behavior of serial sex offenders. Qualitative data were
obtained through the descriptions of the crimes provided by 69 serial sex offenders who were incarcerated in a Correctional
Service of Canada institution. Based on the offenders’ accounts, a descriptive model specific to the hunting process was identified.
This model contained the following nine phases: offender and victim routine activities, choice of hunting ground, victim selection,
method of approach, attack location choice, method to bring the victim to the crime site, crime location choice, method to
commit the crime, and the victim release location choice. The model is discussed according to existing research on serial
sex offenders and environmental criminology. Implications for clinical practice, crime prevention, offender profiling, and
future studies are discussed.