Intentional homicide is one of the top two causes of on-the-job deaths of law enforcement officers in the United States, second only to motor vehicle crashes. Despite preparation in the forms of training, equipment, and tactics, over 90 percent of officers in the United States who are murdered on the job are killed by guns. Prior studies on homicides in the general U.S. population have found that various types of murders, such as stranger homicide or intimate partner homicide, are associated with the rates of gun ownership within a state. With these facts as background, the researchers in a study published in fall 2015 investigated whether a state’s gun ownership and homicide rates affected law enforcement officers’ gun homicide rates or if a different state-level factor could be responsible.