Comparing serial homicides to single homicides: A study of prevalence, offender, and offence characteristics in Sweden

摘要

Multiple and serial homicides constitute around 1.6% of all homicides but have unusually tragic outcomes. The aims of this study were to report the prevalence serial-homicide offences and the characteristics of serial-homicide offenders in a non-North American context. The study included all convicted serial-homicide offenders in Sweden from 1973 to 2012 (n=25), as well as a population-based control sample of single-homicide offenders collected during 2007 and 2009 (n=201). Similar to U.S. findings, approximately 1.6% of homicides could be attributed to serial-homicide offenders. Serial offenders were more often diagnosed with personality disorders and autism-spectrum disorders compared with single offenders; and serial offences more often involved victims who were female and unacquainted with the offender, as well as planning, sexual motives, and asphyxia as method of violence. One third of serial offences involved actions aimed at disguising the manner of death; such actions were considerably less common in single-homicide offences. Few offenders displayed the traditional profile of a serial-homicide offender; however, one third displayed sexual motives, a rate roughly 10 times higher than that in the single-homicide group. The study concludes that serial-homicide offenders should be subjected to forensic-psychiatric examinations and that research involving cross-contextual differences and similarities in serial-homicide offenders is needed.