by Jody DiPerna
In September of this year, Abrams Press released a new book by Jillian Peterson and James Densley titled, “The Violence Project: How to Stop a Mass Shooting Epidemic.” The book is the result of more than four years of work and research.
Both Peterson and Densley believe that understanding the problem is a necessary step to fixing it. The Violence Project work is a statement of hope in a time when it is easy to feel that Americans have become so inured to gun violence that we simply accept it as standard operating procedure, that we are so infected with “massacre fatigue” that we have just learned to live with it. The Violence Project believes that our best hope is to understand the problem, so that solutions can be found.
As the third anniversary of the Tree of Life attack, the Pittsburgh Institute for Nonprofit Journalism (PINJ) sat down via video call to talk to Peterson, a psychologist and Densley, a sociologist, from their homes in St. Paul, Minnesota, where their research center is based and where they both teach. Peterson is a professor of criminology and criminal justice at Hamline University; Densley is a professor of criminal justice at Metropolitan State University.
In the summer of 2017, the two researchers launched The Violence Project, a nonpartisan, nonprofit research center aimed at investigating mass gun violence.They culled through police records and court filings, mined letters and diaries, examined news coverage, looked in social media databases and every corner of the internet, interviewed mental health providers, school counselors, and some of the families of victims of mass shootings. Peterson and Densley also interviewed and corresponded with several convicted killers.
The book is a narrative of what they’ve learned about perpetrators, about the ways that people and places are ripped apart by gun violence, and about the seeming inability to staunch the bleeding. Mostly, they were trying to find ways to understand the problem so that solutions can be found.
Because mass shootings leave such a trail of pain and horror and because they make previously safe spaces unsafe — schools, movie theatres, workplaces, houses of worship — it is easy to view each killer as an unchanging fixed point on a line — a monster. But, Peterson and Densley say, that may not help us find a way forward.
“If somebody is a monster, you can’t fix it. That means you just need more secure doors, and more guns, and more armed guards, because that’s how we protect ourselves from monsters. But, if you’re willing to say, this is a human being who has done a horrifically monstrous thing, let’s figure out the pathway that got them to that point, that’s when you can start having conversations about prevention,” Peterson said.
They wanted to drill down in the ways they could to understand the overlapping causes of mass shootings. Their research shows that 172 mass shootings have taken place in the United States over the last 55 years. More than 1,200 lives have been lost to mass gun violence, leaving scars that criss-cross this nation, in small towns and big cities and places in between.
The FBI tracks incidents of mass violence, using the measurement of four dead as the definition for a mass violent attack. That metric has been adopted universally to track mass-shootings, by groups such as the Giffords Law Center, The Gun Violence Archive and The Violence Project and similar organizations.

Peterson and Daley talked about the ways that we have become inured to mass shootings. They were both frustrated that there are mass shootings that don’t even hit the national news.
“We don’t think that we have a comprehensive list of every mass shooting in this country. If we went down to three or more, our database actually doubles,” Peterson said.
“Sadly, more deaths get more media coverage and that’s what we used to do the work,” she added. .
Densley said this was one of the things that was hardest about the work — seeing the ways that the violence spreads throughout neighborhoods and cities so that it is nearly impossible to have any kind of separation from gun violence.
“Something that we encountered a lot — just how many people’s lives have been touched by this phenomenon. That’s really the most frightening thing — the amount of times we would hear, ‘I was in the shopping mall that day when this happened,’ or ‘It was my best friend’s cousin.’ The six degrees of separation around this issue is unbelievable,” Densley said.
“You realize that each one of these shootings, the ripple effects are massive: it’s hundreds, thousands, tens of thousands of people who can draw a line to the shootings and say that was my friend or that was my cousin,” Densley added.
Peterson and Densley were trying to get at as much raw data as possible. They wanted to understand each mass shooting so they could classify them and try to make some kind of sense out of wholly senseless events.
According to their data, mass shootings have become deadlier over time. In the 1970s, the United States averaged eight deaths per year from mass shootings. Now, we average 51 deaths per year.
Their data also shows that there are 120 guns for every 100 people in the United States. Many of the perpetrators of the 172 attacks tracked by The Violence Project had more than one gun with them at the time when they committed their crimes.
“It’s only a very small percentage of Americans that have the arsenal,” Densley said.
It’s hard to get accurate raw data on gun ownership for a whole host of political reasons, but according to Densley and Peterson, the best estimates show that about ten percent of Americans own half of all the guns.
The project breaks down their findings in several other key ways. 98 percent of these crimes are committed by men. Fifty-two percent of America’s mass shooters are white, 20 percent are Black and eight percent are Latinx. They breakdown the location of the shootings — schools (K-12), colleges and universities, workplace, house of worship, restaurants and bars, and so on. There are also patterns in terms of age.
Peterson explained that there tend to be “clusters” of the ages of the men who commit these crimes. And the correlation between these crimes and suicidal ideation is hard to miss.
“It’s really dramatic. They’re all either early-20s or mid-40s. That really maps on to suicide trends — that it is the early 20s and mid 40s men is the same clusters you see when you look at suicide data,” according to Peterson.
This fact, they said, could be a key to prevention.
“There is a lot of work that needs to be done. I still walked away feeling really hopeful. In interviewing perpetrators, the one question we always asked is, is there anything or anyone that could have stopped you from doing this? And every time they said yes. Every time they said something or someone — probably anyone. I do think that we are capable of getting people through those moments,” Peterson said.