Background: Clinical classification of types of homicide-suicide (HS) was proposed, but no information on empirical-based classification and prevalence of different types of HS was available. This paper aimed to empirically classify HS events into different clusters and to discuss specific evidence-based prevention initiatives.
Method: Data of HS offenders from Coroner's Court were analyzed through a two-step cluster analysis. Number of clusters and appropriate allocations of cases were obtained. External background variables were tested through post hoc tests to explore the differences among clusters.
Results: Two hundred and thirty-one people died in 98 episodes in the study period (1989-2005). The majority of HS offenders were male (n=68, 68.7%) and aged 30-49 (n=62, 62.6%). Domestic killing was the major type of HS in which over 60% of the homicide motivation was related to spousal conflicts or altruistic reasons. Spouses (n=46, 46.5%) and children (n=47, 47.5%) were predominantly the victims. The common killing methods included chopping with weapons (n=33, 33.3%) and charcoal burning (n=22, 22.2%). Six clusters of HS were derived from the cluster analysis and were further reduced to four major classes. Four major classes were dispute, conflicts in a relationship, altruistic, and mental illness. These classes could be differentiated by methods of homicide and suicide, gender of perpetrator, relationship with victim, and indebtedness.
Conclusions: Financial problem, dispute and domestic violence are significant precipitants of HS in Hong Kong. Those people associated with the precipitating factors should be the targets for intervention and prevention.