How to Stop a School Shooter

By Mark Keierleber | September 7, 2021

In a groundbreaking new book, The Violence Project, two criminologists seek to reframe the public discourse around mass murderers and offer a prevention roadmap that could save lives 

We’ve tried hiding from the monsters. We’ve tried running from the monsters. We’ve tried barricading the doors so they can’t come in, and locking them up so they can’t get out. And yet, they keep creeping into our lives — more so than ever before.

The monsters are mass shooters, including those who unleash hell on schools. But metal detectors, active-shooter drills and school-based police are not a sufficient antidote, a duo of criminologists argue in their forthcoming book “The Violence Project: How to Stop a Mass Shooting Epidemic.”

The first step in violence prevention, Jillian Peterson and James Densley write in the book released Sept. 7, is to recognize that mass shooters are far more complex than ghoulish caricatures. And stopping them will take more than one simple solution.

“We’ve been treating this all wrong,” said Densley, a sociologist and criminal justice professor at Metropolitan State University in Saint Paul, Minnesota. “We are expecting these individuals to just be outsiders beyond the reach of help, beyond the scope of our control. And instead, they are our children, they are our neighbors, they are our work colleagues.”

The book’s conclusions were gleaned from a massive undertaking that’s been years in the making. Peterson and Densley, co-founders of The Violence Project, a nonprofit research center, built what they believe is the largest database on mass shooters ever created that spans back to 1966, involving about 180 attacks with more than 1,200 fatalities. Backed by funding from the National Institute of Justice, the U.S. Department of Justice’s research arm, they compared mass shooters’ life experiences across more than 150 variables, like childhood trauma, to identify commonalities. Under the Violence Project’s definition, mass shootings include tragedies that unfold in public locations with four or more victims excluding the shooter and do not stem from domestic violence, gangs, drugs or organized crimes.

They also trekked across the country for interviews with incarcerated killers, their parents and survivors, offering a new window into the lives of shooters and the impulses that make them tick.

Among the book’s key takeaways, the researchers found that more than 80 percent of the youngest mass shooters leaked their plans before the killings and, among those who inflicted mayhem on schools, 70 percent had previously experienced childhood trauma. And perhaps counterintuitively, fatalities were higher in school shootings where armed security was present on campus.

Based on what they uncovered, the book offers a detailed policy roadmap that Densley and Peterson believe could save lives.

In their forthcoming book The Violence Project, criminologists James Densley and Jillian Peterson offer a road map that they believe could solve what they call an epidemic of mass shootings in the U.S. (Courtesy Jillian Peterson)

The data highlight the critical role of schools, said Peterson, a forensic psychologist and criminology professor at Hamline University in Saint Paul. In many instances, shooters faced significant childhood trauma, stemming from issues like physical or sexual abuse and neglect. Just three months before a suspected school shooter killed 17 people at a high school in Parkland, Florida, his mother and sole parent died of pneumonia. Shooters often lacked supportive family connections, but their schools were often ill-equipped to confront those challenges.

“Schools aren’t necessarily resourced to be screening for trauma and providing in-depth mental health resources and working with families on coping mechanisms and teaching social-emotional learning,” she said. “Right now, so many schools are stretched so thin, but as we think about ‘How do we provide resources to prevent violence,’ I think that’s where they should be going.”

Though school shootings remain statistically rare and federal data suggest that campuses have become markedly safer in the last few decades, The Violence Project’s data reveal that mass shootings have become both more frequent and deadlier in recent years. More than half of the country’s mass shootings have occurred since 2000, the researchers found, and 16 of the 20 deadliest tragedies in modern history unfolded during that time. Of the country’s 20 deadliest mass shootings, three occurred in schools.

Though mass shootings happen elsewhere, the U.S. is a clear outlier. After controlling for population, researchers found the U.S. has six times more mass shootings compared to the rest of the world.

Yet as politicians offer “thoughts and prayers” to victims and stand their ground in a gun-control debate caught in a feedback loop, Peterson said that tangible steps can be taken right now to prevent more carnage. In fact, the pandemic offers lessons for prevention. When people stopped gathering en masse in public places like schools and offices, these rampages stopped as the opportunities for mass casualties dried up. Other mechanisms exist to limit opportunities outside a global pandemic. For example, 80 percent of school shooters obtained guns from family members, but no federal law and few state rules require parents to store weapons out of the reach of children. Such laws exist in six states including California, where parents can face arrest for keeping unlocked guns at home. Public information campaigns that promote safe storage could save lives, the book concludes.

“I want people to read this book and feel hopeful, which is not necessarily what you think when you pick up a book about mass shootings,” she said. “There are things that each of us can do.”

The voices of the perpetrators

To understand the motives of mass killers, Peterson and Densley approached the work with a strong dose of empathy. They didn’t lose sight of the reality that the perpetrators had committed horrendous crimes, but their harsh life experiences added context. Understanding the root causes of violent behaviors, they argued, is critical.

Peterson came to that realization on Rikers Island, the notorious jail complex in New York City where she worked early in her career. As a special investigator for the city’s public defender’s office working death penalty cases, she soon recognized: “The worse the crime, the worse the story.”

Densley had a similar experience inside New York City’s public school system, where he worked as a special education teacher before pivoting to researching youth gang violence. The system treated many disabled children as though they were disposable and could never succeed, he said. But Densley wasn’t buying it.

The duo applies a similar framing to mass shooting prevention and as they compared the shootings, clear patterns emerged.

The Violence Project, available Sept. 7, relies on groundbreaking research including the largest database of mass shooters ever created. (Photo courtesy Jillian Peterson)

For many, issues began with childhood trauma. Of the shooters where such data was available, 55 percent had experienced significant childhood trauma, compared to roughly 15 percent in the general population. The trend was even higher among school shooters, about 70 percent of whom had experienced adverse childhood experiences. To understand the role these traumas played, interviews with incarcerated gunmen were especially illuminating, Peterson said.

“They have so much knowledge in terms of how they got to this point,” she said. “We can build datasets and do all this data analysis but, at the end of the day, it’s the voices of these perpetrators saying ‘Here’s how I got here,’ that I think I learned the most from.”

The book intentionally excludes the shooters’ names as part of an effort to deprive them of notoriety, and Peterson declined to disclose their identities due to confidentiality agreements. One in 10 mass shooters sought fame from their attacks, they found, and often idolized other gunmen. For example, at least 20 school shootings have been inspired, at least in part, by the infamous 1999 attack on Columbine High School in suburban Denver. Among them is the 2012 mass school shooting at Sandy Hook Elementary School in Newtown, Connecticut, in which 26 people, including 20 first-graders, were killed.

Among those interviewed for the book was “Perpetrator B,” a school shooter who recalled how his father would sometimes hit his mother, telling the researchers he developed depression in elementary school and became suicidal by 17. People knew he was struggling, he said, “but they never knew how bad it was.” A caring relationship between the perpetrator and an adult mentor could have put him on a different path, the book concludes. Instead, he became obsessed with studying other shooters, including a visit to Columbine High School. He attempted to die by suicide before attacking his former high school.

More than three-quarters of shooters were in a state of crisis before their attacks and left signs that could’ve been identified by those around them. In fact, 86 percent of mass shooters 20 years old and younger leaked their intentions, including in chat rooms and on social media.

The most profound discovery, both researchers agreed, was a significant connection to suicide. Though mass shooters made meticulous plans about their attacks, escape was never part of the equation. A third of mass shooters were actively suicidal prior to their attacks and 40 percent specifically planned to die in the act, they found. Those who were suicidal were more likely to telegraph their plot, suggesting that they may have been crying out for help. Both the shooters at Columbine and Sandy Hook died by suicide after the attacks.

Following the shooting in Newtown, the parents of two victims founded the nonprofit Sandy Hook Promise, which trains students and educators to recognize signs that someone could hurt themselves or others and offers a tip line that allows youth to intervene anonymously.

The reality that many shooters are suicidal “just opened up a whole different line of thinking” Peterson said. For decades, efforts to stop school shootings have centered largely on hardening schools with security. “But if some is actively suicidal, a lot of that stuff doesn’t work.”

The Violence Project’s conclusions are not universally accepted within the community of school-shooting researchers, and Jaclyn Schildkraut, an associate professor of criminal justice at the State University of New York at Oswego, is among the group’s critics. She argued that some of the Violence Project’s findings aren’t sufficiently backed up by research and some of their recommendations “are very dangerous,” including those that critique school security measures.

Schildkraut said that social-emotional learning is important, but the group’s focus on shooters’ traumatic experiences “comes across as, ‘Well, we’re not nice enough to these shooters,’ or ‘We’re not giving them the attention that they need in a more emotional way.’” The data also rely heavily on media reports rather than mental health records, which she said makes it impossible to reach definitive conclusions.

A roadmap to safety

The Violence Project adds a major wrinkle in a violence prevention strategy long employed in schools — an approach Densley called “security theater.” School-based police have grown exponentially in the last several decades, but in measuring their effects on mass school shootings, researchers reached a counterintuitive conclusion.

Of 133 mass school shootings in their data, armed guards were on the scene in 24 percent when the shooting began. In shootings where guards were present, fatalities were three times higher. Because gunmen are often suicidal, the authors speculate that perpetrators could even be drawn to places with armed security.

Schools spend nearly $3 billion on security each year, but the data suggest a softer approach that focuses on addressing the root causes, like adverse childhood experiences, Densley said. Specifically, the book calls for a heightened focus on trauma screenings in schools and doctor’s offices that identify people who are struggling and get them help while avoiding punitive consequences like arrests.

“Instead of spending billions of dollars on all of that unproven technology, let’s hire school counselors,” he said. “Violence prevention is not just building metal detectors. Violence prevention is also crisis intervention in our schools and mental health support in our schools.”

Civil rights groups have long called on schools to hire additional counselors in place of physical security measures like school-based police, a concept that gained momentum after George Floyd was killed by a Minneapolis police officer in 2020.

But Schildkraut isn’t convinced by the Violence Project’s takeaways on school-based police, arguing that a host of factors contribute to the number of fatalities during an attack. Similarly, while the Violence Project has highlighted the potential harms of lockdown drills, Schildkraut’s research has found that they are key to “fostering a culture of preparedness in schools.” It’s important to explore the root causes that motivate people to become violent, she said, but prevention is only part of the solution and shouldn’t come at the expense of emergency response and preparation.

“My concern is that their claims are made from personal perspectives and not evidence-based perspectives because the evidence that’s out there on lockdown drills doesn’t say, ‘These are bad,’” she said. “I would love to live in a world where we don’t need active-shooter drills and contingency plans and everything, but that’s not the society we live in.”

Mental health services are just one part of a multi-pronged approach to violence prevention highlighted in the book, which calls for changes at the individual, cultural and political levels. Individually, for example, people must become more willing to speak up when they believe someone close to them is in crisis, including through anonymous tip lines, and gun owners should lock firearms out of young people’s reach. At a systems level, government programs could expand the social safety net to promote community health by addressing issues like educational inequality, hunger and homelessness.

The authors don’t shy away from what may be the hardest sell: gun control. Specifically, they call for universal background checks and wait times on firearm purchases that “are the functional equivalent of counting to 10 before doing something impulsive,” and “red flag” laws that remove weapons from people who pose a threat to themselves or others.

Densley is acutely aware that his book asks a lot from society. But if everybody plays a small role, the authors believe, we can beat back the ever-recurring “monsters.”

“We can’t just be helpless, we can’t just wait,” he said. “A lot of other books, the final chapter, the conclusion, is ‘Well, all we need is a mighty act of Congress to shut down the gun lobby and we’ll live happily ever after.’ It’s like, ‘Well OK, what do we do between now and never?’”

Lead video by Joe Raedle / Getty Images

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