Coincident deaths: double suicide or murder-suicide?

A retrospective review was undertaken in South Australia over an 11-year period from July 1996 to June 2007 of all multiple, unnatural, non-accidental deaths in adults (> 16 years) looking for cases of double suicide and murder-suicide. All cases had undergone a full police and coronial investigation and full autopsy. There were seven cases of double suicide involving 14 individuals: nine males and five females ranging in age from 29 to 79 years (average 49 yrs). Over the same period there were eight murder-suicides involving 16 individuals: nine males and seven females ranging in age from 17 to 83 years (average 49 yrs). All the murder-suicide perpetrators were male and the majority of the victims were female (7/8). All eight perpetrators committed suicide with gunshot wounds to the head (N = 8; 100%); one victim was manually strangled and the remainder died from gunshot wounds to the head, neck and upper chest. In contrast, all but two of the double suicide victims died of carbon monoxide toxicity, with the remaining couple dying from mixed drug toxicity. While differentiating between these two groups may be difficult, double suicide victims used much less violent methods than perpetrators of murder-suicide and often had histories of chronic debilitating disease. Spousal and familial links characterised both groups.