School shooters usually show these signs of distress long before they open fire, our database shows

Two years before he lined his schoolmates up against a classroom wall and executed them one by one, the student, who would become the gunman, tried to show his English teacher something important.

He had quietly slid up his sleeves to reveal the cut marks running down his arms. The teacher panicked. A novice educator at the time, she had never been coached or trained in what to do in these situations, what to say or how to help. So she passed the student off to another teacher, who then filed a form with the principal’s office. She felt fairly certain nothing else came of it.

“He was asking for help,” the teacher said in reflecting on the encounter during a recent interview. “If I’d had some training to help him, a five-step sheet to follow, say this, say that, maybe I could have made a difference?”

The story is one of dozens that we have collected over the past two years in our effort toward studying the life histories of mass shooters. It typifies what we believe is one of the biggest challenges that schools face when it comes to averting school shootings – and that is recognizing and acting upon warning signs that school shooters almost always give well before they open fire.

We are both criminologists who study aggression and violence. One of us focuses on mental illness among offenders. The other has an extensive background in group violence.

Together, we have built a database of the 160 mass public shootings that have taken place in the United States since 1966 for a project funded by the National Institute of Justice, the research arm of the U.S. Department of Justice. For mass public shootings, we use the common definition of an event in which four or more victims are killed with a gun in a public place.

Protective measures fall short

The goal of our project is to use data to look for patterns in the lives of mass shooters. The purpose is to develop a better understanding of mass shooters and why they did what they did, in order to prevent future tragedies.

Valentine’s Day marks one year since the mass shooting at Marjory Stoneman Douglas High School, in Parkland, Florida, where 14 students and three staff members lost their lives. This year is also the 20th anniversary of the Columbine High School massacre in Littleton, Colorado.

Thirteen people lay down to symbolize those killed in the Columbine school shooting on the 10th anniversary of the Columbine attack, at the Capitol in Denver, Colorado in 2009. Chris Schneider/AP
For two decades, therefore, school leaders, law enforcement officials and policymakers have experimented with ways to stop mass shootings. They have run lockdown drills, produced training videos, armed teachers, hired school resource officers and spent billions of dollars on more secure buildings.

Although gun violence in schools has decreased since the 1990s, our research found that mass school shootings have not decreased over time. There have been six in the last 20 years – Columbine, Red Lake, West Nickel Mines, Sandy Hook, Parkland, Santa Fe – plus 39 attempts in which a shooter came to school heavily armed and fired indiscriminately at numerous people, according to our reanalysis of The Washington Post’s school shooting database. That’s a steady average rate of about 2.4 mass school shootings per year.

2018 was the worst year on record for gun violence in U.S. schools, with 97 incidents and 56 deaths, compared to previous highs of 40 in 1993 and 38 in 2012, the year of the Sandy Hook Elementary School massacre in Newtown, Connecticut.

Patterns emerge among shooters

Our initial analysis of the school shooting data found some noteworthy patterns. All of the K-12 school shooters or would-be school shooters were male, between the ages of 12 and 17. The majority were white and nearly all – 91 percent – were students or former students at the targeted school.