Offender Profiling in Cases of Swedish Stranger Rapes

Detta är en avhandling från Stockholm : Department of Psychology, Stockholm University

Sammanfattning: Swedish national statistics suggest that the number of reported stranger rapes is steadily increasing. Stranger rape is one of the most difficult types of crime for the police to investigate because there is no natural tie between the victim and offender. As a result, there is a need for more knowledge about how crime scene features could be used to make inferences of likely offender characteristics that could help investigators narrow down the pool of suspects. The aim in Study I was to examine how offender behaviors interact with contextual features, victim behaviors, and the assault outcome. Results suggest that the stranger rapes could be distinguished by five different dynamic rape pattern themes, which mainly differed on two dimensions: level of violence to control the victim, and level of impulsivity/premeditation characterizing the rapes. The results also highlight the importance of including contextual features when studying offender behaviors. The aim in Study II was to examine how single-victim rapists and serial rapists can be differentiated by the actions at their first stranger rape. Results suggest that three behaviors in conjunction: kissed victim, controlled victim, and offender drank alcohol before the offense, could be used to predict whether the offender was a single-victim rapist or serial rapist with a classification accuracy of 80.4 %. The aim in Study III was to examine how stranger rapists could be differentiated from a normative sample on background characteristics, and if stranger rapists’ pre-assault and initial-attack behaviors could be used to predict likely offender characteristics. Results showed that the strongest predictions could be made for previous criminal convictions, offender age, and the distance traveled by the offender to offend. Overall, the present thesis has found some scientific support for the use of crime scene behaviors to make inferences of likely offender characteristics that could be useful for profiling purposes.