Can Serial Rapists be Distinguished from One-off Rapists?

There are investigative advantages to being able to determine early in a police investigation whether a rape has been committed by a serial or a one-off rapist. Previous research has found some differences in the crime-scene behaviors of serial and one-off rapists; however, this research suffers from the limitation of utilizing a sample of rapes within which there was a mixture of victim-offender relationships. To address this limitation, this study sampled 38 serial (two or more convictions) and 50 one-off (one conviction) stranger rapists and compared their crime scene behavior across four domains (control, sex, escape and style behaviors). Serial and one-off rapists differed in some control and sexual behaviors, in particular, in the type of victim targeted, the offense locations, methods of control and the sexual acts forced upon the victim. However, the results did not indicate a striking difference in the offending behavior of the two groups. The implications of these findings for criminal investigations are discussed.