One-third of the attackers who terrorized schools, houses of worship, or businesses last year had a history of serious domestic violence, two-thirds had mental-health issues, and nearly all had made threatening or concerning communications that worried others before they struck, says .
The Secret Service studied 27 incidents in which a total of 91 people were killed and 107 more injured in public spaces in 2018. Among them: the shooting at Marjory Stoneman Douglas High School in Parkland, Fla., where 17 people were killed.
The report analyzes the timing, weapons, locations, and stressors of the attacker, plus events that led up to the incident, in an effort to better understand how such attacks unfold and how to prevent them.
Most attackers were male, ranging in age from 15 to 64. While 67 percent had mental-health issues, only 44 percent had a diagnosis or known treatment for the issue.
More than half the attackers had a grievance against a spouse or family member, or a personal or workplace dispute. Also, 22 percent had no known motive. In nearly half the cases, the attacker apparently selected the target in advance.