ST. PAUL, Minn. – The Thousand Oaks, California mass shooting marks another public place that has become a site of horror and bloodshed.

How is it our nation has arrived at the point when the news alerts don't surprise us, when we don't even go a week between mass shootings anymore?

Stay horrified.

That’s the advice from Jillian Peterson, Ph.D., a psychologist and assistant professor of criminology at Hamline University in St. Paul. She will add this latest mass shooting in California to the first database of mass shooters of its kind in the country. The mass violence database analyzes every mass shooting in America since 1966. It lists 155 mass shooters, and now, another.

“It's getting exhausting, we've now had three in two weeks, now we are in the middle of what we call a cluster,” said Peterson.

The database codes and categorizes 155 mass shooters by 60 different variables of their life history, factors like trauma, substance abuse, mental health history, role models, family dynamics, immediate stressors, whether shooters leaked plans, displayed warning signs, suicidality, as well as examining their access to guns.

“One big finding, there was no pattern, and as a researcher that is a little disappointing, we were looking for clusters in the data,” said Peterson. “What we did find, it was the number of risk factors people had was pretty consistent. It wasn’t just mental illness, just being bullied, or not just a traumatic childhood. It was a slow build of things over time, and there was usually an immediate trigger; a break-up, losing a job, or something that pushed somebody over the edge.”

The database also found that shooters often were suicidal before they planned a massacre, and many shooters had a military background, as in the case with the shooting at the Thousand Oaks, CA bar.

Peterson collaborated with her counterpart, Dr. James Densley, associate professor of criminal justice at Metro State, and a team of undergraduate researchers. Their project caught the attention of the federal government and now the database can enter a new phase of research, boosted by a recent $300,000 grant from the U.S. Department of Justice.

The funding will allow Peterson and Densley to personally interview five living mass shooters who are currently incarcerated.

“We will also be going to the communities where those mass shooting occurred and interviewing people in the community,” said Petersen. “I think it's hard because it sounds like we are humanizing people who have done something awful, but the point of this is actually to prevent new victims and it's for the victims, if we are going to stop this from happening we have to be willing to hear these stories. The goal of this is really to come up with prevention strategies that actually can be effective and stop this crisis we are in.”

On Friday, Nov. 9, The Hamline Center for Justice and Law will release the first public report from the findings of their database, in an event called Mass Shootings: Pathways to Prevention.

In addition to detailing the mass shooter database project, Peterson and her team plan to include answers to public policy questions about mass shootings and mental illness, gun access, social media, and warning signs. The hope is their research will have implications for innovative, evidence-based prevention strategies for schools, workplaces, and public events.

Learn more about the event here.