Behavioural linking of stranger rapes (original) (raw)
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Crime scene actions and offender characteristics in a sample of Finnish stranger rapes
Journal of Investigative Psychology and Offender Profiling, 2004
The crime scene actions employed by offenders in stranger rapes were analysed in relation to offender characteristics. Data were drawn from an official police database and consisted of stranger rapes occurring in Finland between 1992 and 2001 (n = 100). The structure of dichotomous variables derived through a content analysis of crime scene actions and offender characteristics were analysed with non-metric multidimensional scaling (MDS). The first analysis revealed three separate action themes, with thematic emphases on Hostility, Involvement or Theft. The MDS-solution for offender characteristics suggested four themes: Conventional; Psychiatric/Elderly; Criminal/Violent; and Criminal/Property. Each case was assigned to one of the themes or as a hybrid in order to analyse the associations between action themes and characteristics. The only significant association was found between the action theme, Theft and characteristics theme Criminal/Property. The results are discussed in relation to previous research. Copyright © 2004 John Wiley & Sons, Ltd.
Statistical modelling in the investigation of stranger rape
Journal of Investigative Psychology and Offender Profiling, 2010
A sample of stranger rape offences (n = 271) registered in the Dutch Violence Crime Linkage Analysis System database in the Netherlands between 1997 and 2007 was studied with the objective of developing statistical models, which give an indication of the probability of basic offender characteristics. Observable crime characteristics concerning the modus operandi, interaction between the offender and the victim, violence, precautionary measures, and sexual behaviours were selected in the dataset. Offender characteristics were selected based on their usefulness for the police organisation in narrowing the scope of a criminal investigation. Spatial behaviour, criminal history, and living situation of the offender were selected. From the predictive models, four out of fi ve achieved a correct rate of over 70%, and all models predicted better than the best guess method. The proposed models for distance and prior convictions for violence seem particularly promising. Both these models show an improvement of correctly predicted offender characteristics of more than 20 percentile points compared with that which could have been estimated based on the average in the total sample. The predictive value of the models needs to be tested further with 'new offences', which were not used to construct the model. In general, the current study supports the fi nding that crime characteristics can be used to get an indication of the probability of certain offender characteristics. Nevertheless, for an understanding of the relationship between the crime characteristics and offender characteristics, a further development of a theoretical framework is urgently necessary.
Differentiating sex offences: a behaviorally based thematic classification of stranger rapes
Behavioral Sciences & The Law, 2003
It is hypothesized that stranger rape victim statements will reveal a scale of violation experienced by the victim, ranging from personal violation, through to physical violation, and finally, at the most extreme level, sexual violation. It is also hypothesized that offences can be differentiated in terms of one of four themes: hostile, controlling, stealing, or involving. To test these hypotheses, crime scene data from 112 rapes were analyzed by the multi-dimensional scaling procedure Smallest Space Analysis. The results provide empirical support for a composite model of rape consisting of four behavioral themes as different expressions of various intensities of violation. The results also suggest that stranger rapes may be less about power and control than about hostility and pseudo-intimacy. The proposed model has implications for the classification of rape, the investigation of sexual crimes, and the treatment of victims.
Forensic Science International, 1992
In this paper it is proposed that the behaviour of an offender during a sexual assault can bs considered as consisting of three main groupings or 'aspects'. These have been termed 'Modus Operandi', 'Sexual and Personal Gratification' and 'Attitude and Intimacy'. Although an oversimplification, such a model facilitates a preliminary description of the offender which can be of direct assistance to an investigating officer. Various factors affect the consistency and variability of behaviour and the model has formed a basis for the development of a concept as to which behaviours might be the more useful for identifying linked offences. This more systematic approach to the investigative and intelligence processes is reliant on a victim's statement containing very detailed information about the offender's actions, together with a record of as much of his speech as can be recollected. The material required is described using the model and the text is illustrated with case examples. Instances are quoted of the possible inferences and their relevance to the investigation of sexual offences.
Psychological Profiling of Offender Characteristics From Crime Behaviors in Serial Rape Offences
International Journal of Offender Therapy and Comparative Criminology, 2002
Criminal psychological profiling has progressively been incorporated iuto police procedures despite a dearth of empirical research, bMeed, in the study of serial violent crimes for the ptupose of psychological profiling, vet 3, few orightal, quantitative, academically reviewed studies actually exist. This article reports on the analysis of 62 incidents of serial sexual assault. The statisticaI procedure of multidimensional scalhtg was employed in the analysis of this data, which in turn produced afire-cluster model of serial rapist behavior First, a central clnster of behaviors were identified that represent common behaviors to all patterns of serial rape. Second, four distinct outlying patterns were identified as demonstratbtg distinct offence styles, these being assigned the following descriptive labels bratalit3; intercourse, chaotic, and ritual. Furthermore, analysis of these patterns also identified distinct offender characteristics that allow for the use of empirically robust offender profiles in fi¢ture serial rape investigations.
Psychology, Crime & Law, 2006
Crime scene profiling has received considerable attention, particularly in popular media. First, since low inter-rater reliability would affect the validity of profiling, we tested inter-rater agreement for 33 variables often used in manuals for the coding of crime-related behaviour. Thirty cases were chosen randomly from 146 cases of assault rape with unknown male offenders in Sweden during 1990 Á1994. Second, we used multidimensional scaling (MDS) with all 146 cases to replicate earlier work by Canter and Heritage (Journal of Forensic Psychiatry, 1, 185 Á212, 1990) regarding motivational dimensions in unknown assault rapists. On average, inter-rater reliability was good; physical behaviours were more reliably coded than were verbal behaviours. However, a two-dimensional MDS solution with the motivational dimensions suggested by Canter and Heritage was not replicated. We argue for better empirical support for the inclusion of specific variables in coding formats for crime scene information. This is particularly important for analyses like the MDS, since the number, representativity, and intercorrelations of such variables could affect results considerably.
Applying crime scene analysis to the prediction of sexual recidivism in stranger rapes
Law and Human Behavior, 2013
The current study sought to improve the predictive accuracy of sexual recidivism using the Static-99 risk assessment tool by the addition of detailed crime scene analysis (CSA). CSA was carried out using a Behavioral Thematic Analysis (BTA) approach, the gold-standard in CSA. BTA was conducted on a sample of 167 stranger rape cases using nonmetric multidimensional scaling (MDS). The BTA procedure revealed three behavioral themes of hostility, criminality, and sexual exploitation, consistent with previous research in sexual offending CSA. Logistic regression analysis indicated that the criminality theme was significantly predictive of sexual recidivism and also significantly correlated with previous sexual offense history. Further, the criminality theme led to a significant increase in the incremental validity of the Static-99 actuarial risk assessment instrument for the prediction of sexual recidivism.
International research has suggested that rapist criminal histories can be predicted from certain offence behaviours. Ninety-six solved stranger rape cases were examined to determine if there was consistency in a New Zealand sample. Rapist behaviours during the offence were compared with criminal convictions prior to the rape. The primary statistical technique used was likelihood ratio stepwise binary logistic regression. Predictive utility of the results was limited, due to significant correlation coefficients between the criminal history variables. Nevertheless, the current study reflected the general findings of similar descriptive international research. These outcomes were: the majority of stranger rapists had prior criminal convictions, and the majority of those convictions were for property offences not sexual offending. Furthermore, ethnic minorities were over-represented among the offenders, and the majority of stranger rapists started committing their first known rapes in their midto late 20s. Finally, methodological difficulties were encountered during this study. This highlights the need to refine existing statistical approaches to predictive offender-based research.