EPA-1679 – Homicide, psychosis and geographic profiling – a population-based study of all homicide cases in Sweden 2007-2009

Abstract

It is believed that mentally disturbed offenders commit their crimes closer to their residence compared to other offenders; however, scientific data in this area is scarce. Do mentally disturbed homicide offenders commit their crimes closer to their residences than other offenders? To examine the distances between homicide offenders’ residences and crime scenes, and correlate distance to occurrence of severe mental disorder. All homicide offenders in Sweden between January 1, 2007 and December 31, 2009 were identified through an official crime register and a forensic medicine database (n=249). Offender data was collected from police files, court verdicts, forensic psychiatric evaluations, and the National reception unit at the Prison and Probation Services. Coordinates for offenders’ homes and crime scenes were used to calculate Euclidic distance. Data is presented using descriptive statistics. As outcome data (distance travelled to crime scene) was highly skewed, non-parametric tests were used (Mann-Whitney test). 7% of offenders had a psychotic disorder (n=17). All but one committed the crime within, or close to, their residence (mean distance 0.7 km; median 0 km) compared to other offenders (mean distance 25.7; median 0.9 km). Offenders who committed the crime >100 km from their residence were rarely found to have a severe mental disorder, and more often had an instrumental motive; e.g. money or sexual abuse. Mentally disordered offenders seem to commit offences in close proximity to their residence. This finding may have implications for police investigations, geographic profiling and forensic psychiatric evaluations.