Murdering the person closest to you: Similarities and differences between intimate partner sexual homicide and non-intimate partner sexual homicide.

Sexual homicides (SHs) demand nuanced research for effective prevention, treatment, risk assessment and theoretical insights. Intimate-partner sexual homicides (IPSHs), comprising approximately 20% of SHs, have received limited attention. This study compares IPSHs (n = 56) and non-intimate partner sexual homicides (NIPSHs) (n = 236) in Australia and New Zealand by investigating offender, victim, and crime-scene characteristics. While IPSH perpetrators were typically older, separated, and had prior domestic violence convictions, victims were more often non-white with histories of domestic violence and substance use. Although crime-scene locations and post-offence behaviours differed, similar crime scene behaviours were displayed across offender groups, which seemed to be routed in different underlying motives. Whereas drivers of IPSH commonly were grievance and anger, associated with offences occurring after arguments, drivers for NIPSH were more often sexual deviance and sadism. Overall, IPSH encompasses aspects of domestic violence, homicide, and sexual violence, distinguishing it from SH.