One of the surest ways to prevent a mass shooting is to identify potential threats before they actually attack. Often the threats are “insiders”.

James Densley, co-founder of the Violence Project and a criminal justice professor at Metropolitan State University, said researchers looked at factors in the lives of shooters, including mental health troubles, whether they considered suicide, and how they had access to guns. These findings were reported in the New York Times/Associated Press:

“For a start, we need to be a little bit more attuned to the fact that people are in crisis, and are looking for help, and perhaps aren’t getting it.” Researchers found that 98 percent of mass shooters were men and that 52 percent were white. The proportion of mass shooters who had been diagnosed with mental health conditions was only slightly higher than the general population, according to researchers.

Importantly, school mass shooters are most often insiders. Here are more recent tools to help with threat assessments: