Mass attacks are back in the news following two recent California shootings that left 18 people dead. Despite the seemingly random nature of these attacks, many are triggered by workplace issues and take place in business settings.

A new report from the National Threat Assessment Center of the Secret Service investigates 173 mass attacks from 2016 to 2020 in which three or more people were harmed. Among the key findings:

• Most attackers exhibited behavior that caused concern in family members, friends, neighbors, classmates, co-workers, and others. In many cases, these individuals feared for the safety of themselves or others.
• Many attackers had a history of physically aggressive or intimidating behaviors, evidenced by previous violent-crime arrests or 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, many of which 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 in various areas of life, including family or romantic relationships, employment situations, and legal issues. In some cases, attackers experienced a specific triggering event before perpetrating the attack.
• More than half of the attackers experienced mental health symptoms before or at the time of the attack, including depression, psychotic symptoms, and/or suicidal thoughts.

As the nation searches for solutions, employers can play an important role. Enhanced mental health benefits may be especially important in the wake of the pandemic and at a time of economic uncertainty.

Employers also should anticipate the unexpected. "Businesses should consider establishing workplace-violence prevention plans to identify, assess, and intervene with current employees, former employees, and customers who may pose a risk of violence," the Secret Service report says.