A new, comprehensive study of mass shooters—covering every killing of at least four people in a public place since 1966—has found four factors that connect nearly all of them. The Violence Project compiled data starting with the University of Texas shootings, when 15 people were shot to death from an observation deck on campus—picked because that was the first mass shooting heavily covered by broadcast news, Vice reports. The study is the largest of its kind ever funded by the federal government. Mass shootings are rising, the data showed: One-fifth of the 167 attacks over those 53 years have taken place in the past five years. The findings also offered hope for prevention. More than 80% of shooters experience a crisis before they attack, the study's authors wrote in the Los Angeles Times. So intervention at school and work by mental health professionals could have an impact. "Those are opportunities for prevention," said Jillian Peterson, a co-author.
The researchers found that the shooters usually have suffered a childhood trauma, are having a personal crisis or nursing a grievance, can cite examples that illustrate the wrongs, and have access to a gun. The data points to five broad types of shooters, per Vice: those who open fire at a K-12 school, college, workplace, place of worship or a store, restaurant or other commercial spot. The profile varies by target—workplace and church shooters are older than the others, for example. The study's authors said their goal is to increase understanding of mass violence, leading to ways to reduce it. "That will take moving beyond party lines over gun control to plan and implement data-driven, evidence-based solutions," they wrote in the Times. (Read more mass shootings stories.)