Secret Service Finds Common Themes Among Mass Attackers

WASHINGTON - The 23 mass attacks on US soil last year resulted in 147 deaths, nearly 700 injuries and violated a sense of safety for all Americans going about their daily lives.

The Secret Service National Threat Assessment Center (NTAC) examined the attacks and identified themes for assessing future threats in a new report.

They found some common threads whether the attacks occurred at schools, the workplace, or were considered an act of terrorism.

Here's what they found:

• Nearly half were motivated by a personal grievance related to the workplace, a domestic issue or other issue.
• More than half had histories of criminal charges, mental health symptoms and/or substance abuse problems.
• All had at least one significant stressor within the last five years.
• More than half were dealing with financial instability.
• More than three quarters made concerning communications and/or elicited concern from others prior to their attacks.

Researchers conclude the themes "highlight the importance of gathering information on a person's background, behaviors, and situational factors; corroborating the information from multiple sources; assessing the risk the individual poses for violence; and identifying intervention points to mitigate that risk."

Most of the attacks, 82 percent, were carried out using a firearm.

Of the 23 attackers who used guns, at least 10 possessed their weapons illegally.

Vehicles and knives were used for the remaining attacks.

All of the attackers were male and ranged in age from 15 to 66.

Nearly two-thirds of them experienced mental health symptoms prior to their attacks, including paranoia, hallucinations, delusions and suicidal thoughts.

A history of mental illness was present in most of the attackers who were motivated by ideology or racial bias.