Most mass attackers exhibited behavior that concerned family members, friends, neighbors, classmates and co-workers prior to taking violent action, according to Mass Attacks in Public Spaces: 2016 to 2020,  a comprehensive report released by U.S. Secret Service National Threat Assessment Center (NTAC) that examined 173 incidents of targeted violence and highlighted the observable commonalities among the attackers.

The attacks contained within the report impacted a variety of locations, including businesses and workplaces, schools, houses of worship, military bases, residential complexes and more. In many of these cases, the attackers had a known affiliation with the site of the attack.

The analysis is intended to provide critical information to a cross-sector of community organizations that have a role in preventing these types of tragedies. Among the report’s key findings:

• Most of the attackers had exhibited behavior that elicited concern in family members, friends, neighbors, classmates, co-workers and others, and in many cases, those individuals feared for the safety of themselves or others.
• Many attackers had a history of physically aggressive or intimidating behaviors, evidenced by prior violent criminal arrests/charges, domestic violence or other acts of violence toward others.
• Half of the attackers were motivated by grievances and were retaliating for perceived wrongs related to personal, domestic or workplace issues.
• Most of the attackers used firearms and many of those firearms were possessed illegally at the time of the attack.
• One-quarter of the attackers subscribed to a belief system involving conspiracies or hateful ideologies, including anti-government, anti-Semitic and misogynistic views.
• Many attackers experienced stressful events across various life domains, including family/romantic relationships, personal issues, employment and legal issues. In some of these cases, attackers experienced a specific triggering event prior to perpetrating the attack.
• Over half of the attackers experienced mental health symptoms prior to or at the time of their attacks, including depression, psychotic symptoms and suicidal thoughts.

The report also highlights key operational implications for those tasked with violence prevention. These implications should be kept in mind while communities develop the tools, training, resources and policies to prevent future tragedies.

“The prevention of mass violence in America remains as critical as ever. Far too often, communities and families have been devastated by the impact of these tragedies, and public safety professionals continue to work toward preventing future attacks,” said U.S. Secret Service Director Kimberly Cheatle of the report. “The information revealed in this report is intended to guide those prevention efforts. NTAC’s exploration of each attacker’s background, motivation and pre-attack behavior will assist the Secret Service and our partners in our shared violence prevention efforts. We encourage our public safety partners to review the information within this report and apply it to their own practices for providing a safe environment in communities across the country.”

The full report can be found here.