Here's What Mass Attackers Have in Common

Almost two-thirds of assailants who carried out 28 mass attacks on US soil in 2017 showed symptoms of mental illness before the attacks. And that wasn't the only commonality, according a Secret Service report released Tuesday, per USA Today. It examines mass attacks last year in public places like businesses and schools, including the June 14 shooting at a Congressional baseball practice in Virginia; the Aug. 12 attack at a rally in Charlottesville, Va.; the Oct. 1 mass shooting in Las Vegas, the deadliest shooting in modern US history; and the Nov. 5 massacre in Sutherland Springs, Texas, dubbed the worst mass shooting in the state's history. Details:

• 23 of the assailants used a firearm and 10 possessed them illegally; the other attacks were by vehicle (3) and knife (2).
• 82% showed signs of "aggressive narcissism" and 79% engaged in threatening or concerning communications or conduct beforehand.

• 71% had a criminal history, 64% had a history of violence, a third had a history of domestic violence, and more than half had a history of drug or substance abuse.
• 46% were motivated by a personal grievance, while 21% of attacks were ideologically or racially motivated. Mental health symptoms such as paranoia and delusions were a factor in the motive for 14% of attacks.
• Of the 64% assailants who showed mental health symptoms before their attacks, just 25% had received some type of treatment, according to the report, which aims "to identify key themes for enhancing threat assessment and investigative practices" in order to "prevent these types of attacks."
• The similarities between assailants show authorities are right to investigate a person's background, behaviors, and risk factors for violence, and identify "intervention points to mitigate that risk," the report concludes.

(More mass shootings stories.)