Suicide Following Homicide in the Family
Cooper, Mary, Eaves, Derek, Violence and Victims
Previous research has established that perpetrators of homicide-suicide share more characteristics with those who commit suicide than they do with those who commit homicide without suicide. This article examines the characteristics of victims, perpetrators and the circumstances leading to the homicide of a sample of familial homicide-suicides and familial homicides in southwest British Columbia. A familial homicide was defined as one in which the victim and perpetrator were related directly or indirectly through blood or an intimate relationship. Suicide only occurred following the killing of an intimate partner and/or offspring. Consistent with an evolutionary perspective, homicides followed by suicide were most often attributable to male proprietariness (manifested by killing former intimate partners or offspring following an intimate separation) or mental illness. By contrast, none of the murders which occurred as a result of violence by the victim, child abuse, family conflict, or financial/criminal motives was followed by suicide.
Killing a blood relative or a relative by virtue of marriage (legal or otherwise) is a relatively rare event, at least in comparison with opportunity. While homicide rates vary widely among countries (Boyd, 1988), family homicide rates are somewhat less variable (Daly & Wilson, 1988) and Coid (1983) has shown that rates of homicide-suicide are even more stable. Together, these facts mean that, in countries with low homicide rates, a higher proportion of homicides are of the "domestic" variety and a significant number of those are followed by suicide of the perpetrator.
Coid (1983) interprets the relative constancy in rates of homicide-suicide as reflecting the underlying prevalence of major mental illness. In a major and unique contribution to the study of homicide and homicide-suicide, Daly and Wilson (1988) too accord a significant etiological role to mental illness, but they consider this from the perspective of evolutionary psychology. According to this view, insanity is defined as a "lack of a speciestypical nepotistic perception of fitness interests or the loss of will to pursue such interests" (p. 80).
This evolutionary psychological view of the disordered mind can be used to predict the sorts of cases in which the killer is especially likely to commit suicide or to be found insane. Whichever category of homicides is most clearly contrary to the killer's fitness interests is the madder act; it should be relatively unlikely to occur at all; and when it does occur, it should be relatively likely to be followed by suicide or an insanity verdict. The obvious example is killing kinfolk: to kill one's relative is madder than to kill one's nonrelative, and is, as expected, both relatively rare and relatively likely to be followed by suicide or by an insanity verdict. Other comparisons reveal the same pattern. Killing one's natural child is madder than killing a stepchild, for example, and is indeed rare relative to opportunity. Among 322 Canadian killers of natural children, 20% committed suicide and 11% were found insane; among 59 killers of stepchildren, only 10% committed suicide and a single individual was found insane. Killing one's older natural child is madder than killing one's infant child, and is indeed less frequent, (p. 217)
Most previous research on homicide-suicide has focused on comparisons of the perpetrators with individuals who only committed homicide or individuals who only committed suicide (e.g., Berman, 1979; Fishbain, Rao, & Aldrich, 1985; Palmer & Humphrey, 1977; West, 1965). All of these authors concluded that homicide-suicide perpetrators are more similar to suicides than to cases involving homicide only. All used the relationship between the homicide victim and the homicide perpetrator as a descriptive or dependent variable. All concluded, as might be expected from Daly and Wilson's examination of the much larger database of Canadian homicides, that a higher proportion of perpetrators committing suicide following a homicide was related to the homicide victim compared to those committing homicide only. …