Two Twin Cities researchers are building a database of mass shooters with the goal of better understanding why mass shootings happen and identifying ways to prevent them.

Two Twin Cities researchers are building a database of mass shooters with the goal of better understanding why mass shootings happen and identifying ways to prevent them.

Jillian Peterson, a Hamline University assistant professor of criminology and criminal justice, and James Densley, an associate professor of criminal justice at Metropolitan State University, are working on the project, Minnesota Public Radio reported.

The researchers are focusing on shootings that occurred in a public place and had four or more victims. The shootings are also not family or gang-related. They code shootings based on 50 different variables.

Peterson said they research shooters' past trauma, their family, mental illness, relationships with other people and social media profiles.

While researchers are still in the process of compiling the database, Peterson said she's noticed two characteristics — hopelessness and a desire to achieve notoriety in life or in death.

But it's difficult to predict mass shootings because many people who fit the profile never commit a shooting, Peterson said.

"The problem is that finding a mass shooter is like finding a needle in a haystack," she said.

Stephen Paddock, the alleged shooter in the recent Las Vegas shooting, is different compared to the data compiled so far, Peterson said. He's significantly older than the average shooter and also seems to lack a social media presence, she said.

Peterson said they hope to make the database available to the public once it's complete, but said she's hesitant about how the data will be used.

"People can be labeled and be seen as risky and they're not, and I think we don't want to start picking up people because they seem risky," Peterson said.

Information can be important and powerful, but it's important to recognize its limits, she said.