Firearm Use Increases Risk of Multiple Victims in Domestic Homicides.

Domestic homicides account for more than one in four homicides in the United States and frequently involve multiple victims. This study examined the prevalence of firearm use in domestic homicides in the United States and the associated risk of a multiple homicide event. We used weighted negative binomial regression to model the effects of firearm use on the number of additional victims in domestic and nondomestic homicides using data from the Federal Bureau of Investigation's Supplementary Homicide Reports. Results showed that firearms were used in 54.1 percent of domestic homicides. Firearm use was associated with a 70.9 percent and 38.7 percent increased incidence of additional victimization in domestic and nondomestic homicides, respectively. Whereas male and female perpetrators differed minimally in the likelihood of additional victims in domestic homicides committed with a non-firearm (3.6% versus 2.5%), males were nearly three times more likely to have multiple victims in domestic homicides involving a firearm (6.9% versus 2.4%). Interaction tests showed that the risk of additional victims associated with firearm use was stronger in domestic situations than in nondomestic situations and among male perpetrators. These findings highlight the risk of multiple homicides in domestic homicide situations and the role of firearms in expanding the risk of victimization beyond a single victim.