A Descriptive Study of the Characteristics of Homicide-Suicide in Forensic Autopsy Cases

Homicide followed by suicide (HS) is a tragic event with varied characteristics across countries and regions. Compared to Western countries, there are limited studies on HS in Asian countries. Therefore, this study aimed to clarify the characteristics of recent HS cases by examining forensic autopsy records from 2008 to 2020 collected from the Department of Legal Medicine, Chiba University, in Japan. A total of 77 HS cases were identified, involving 77 perpetrators (52 completed suicides, 25 attempted suicides), with 28 perpetrator and 89 victim autopsies. Our findings showed that older adults accounted for nearly half of the victims; victims were mostly females, whereas most perpetrators were male. The most common HS relationship was that between a parent and a child. Autopsy findings showed that the most common cause of death was strangulation, and illegal drugs were detected only in a few cases; however, psychotropic drugs were detected in child victims. No obvious evidence of past child physical abuse by caregivers was found. In contrast, intimate partner violence (IPV) was present, with a history of IPV found in half of HS cases involving adult intimate partner relationships. Notably, gender differences in age and relationship to the victim were identified. Likewise, some perpetrators may have expressed their plans and intentions for HS before the event, which may represent an important sign for HS prevention. However, to accurately reveal the course of HS, nationwide integrated statistics, forensic autopsies, including toxicological analyses of the deceased; and forensic psychiatric perspectives, including psychological autopsy, are required.