This study investigates the convergent and predictive validity of behavioral crime scene indicators of sexual sadism in the context of rape and sexual homicide. The study is based on a sample of 268 adult males sentenced to a federal penitentiary in Canada. Information regarding crime scene behaviors was gathered from police records, a clinical interview with a psychologist, and a semistructured interview with the offender. A series of logistic regressions were performed to determine whether behavioral crime scene indicators of sexual sadism were associated with an official diagnosis of sexual sadism and were able to distinguish between sexual aggressors against women and sexual murderers. Findings suggest that several crime scene behaviors overlap with an official diagnosis of sexual sadism as well as being able to distinguish between sexual aggressors of women and sexual murderers. Importantly, the majority of crime scene behaviors associated with a clinical diagnosis of sexual sadism are not the same as those associated with sexual homicide.

This study explored the role of age at release on the risk of reoffending using a sample of sex offenders. It examined whether the risk of reoffending, assessed using actuarial tools, should be adjusted according to the offender's age at the time of release. The sample comprised 553 offenders, all of whom were consecutive admissions to a Canadian federal penitentiary. Scores on the Static-99 as well as age at release were included in successive nested prediction models using Cox-regression. Receiver operating characteristic (ROC) curves and Allison's R2 were computed to assess the predictive accuracy of the models and the strength of the association between the covariate measures of general and violent/sexual reoffending. Results showed that overall predictive accuracy observed across models was fair at best. Generally, age of onset and age at release improved the prediction accuracy over and above the scores on the Static-99. In fact, by itself, age at release showed a predictive accuracy comparable to that of the actuarial tool. The results suggest that risk assessors should adjust the risk of reoffending based on the offender's age at release. The implications of this study are discussed in light of the age-crime curve literature and the risk management of sex offenders in the community.

The empirical literature on sexual homicide has posited the sexual murderer as a unique type of offender who is qualitatively different from other types of offenders. However, recent research has suggested that sexual homicide is a dynamic crime and that sexual assaults can escalate to homicide when specific situational factors are present. This study simultaneously explored the utility of the sexual murderer as a unique type of offender hypothesis and sexual homicide as a differential outcome of sexual assaults hypothesis. This study is based on a sample of 342 males who were convicted of committing a violent sexual offense, which resulted in either physical injury or death of the victim. A series of latent class analyses were performed using crime scene indicators in an attempt to identify discrete groups of sexual offenders. In addition, the effects of modus operandi, situational factors, and offender characteristics on each group were investigated. Results suggest that both hypotheses are supported. A group of offenders was identified who almost exclusively killed their victims and demonstrated a lethal intent by the choice of their offending behavior. Moreover, three other groups of sex offenders were identified with a diverse lethality level, suggesting that these cases could end up as homicide when certain situational factors were present.

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