Published: April 15, 2024 By

Twenty-five years ago this week, two Columbine High School 12th graders gunned down 12 classmates and one teacher at their Littleton, Colorado, school in what was, at that point, the deadliest school shooting in U.S. history.

It would hardly be the last.

That grim record has been broken at K-12 schools multiple times since, most recently in 2022, when two teachers and 19 youth under age 11 died in Uvalde, Texas.

Already in 2024, 78 people have lost their lives in 88 shootings at K-12 schools in the U.S. And deaths from mass shootings in general have increased 141% in the last decade, notes Beverly Kingston, director of the Center for the Study and Prevention of Violence at CU Boulder.

“I look at these numbers and I am horrified,” she said. “But I also have so much hope. We know what works to prevent violence. We just need to do it.”

Beverly Kingston


We can prevent violence, and I’ll spend the rest of my life working toward this goal.”
–Beverly Kingston

CU Boulder Today sat down with Kingston to discuss how Columbine changed us and what we’ve learned since.

Where were you on April 20, 1999?

I had just been accepted to a PhD program here at CU Boulder, where I was coming because of the work of the center. I was shocked—eyes glued to the TV just like everyone else was. There had been a few mass shootings before then, but Columbine surpassed everything that was imagined.

How did this incident change things?

It was a call to action. It changed the way law enforcement responds to mass violence, with active shooter training now the norm. It changed how we, as a society, prepare for crises: Sadly, it’s normal for young people in schools across the country to be involved in drills now.

Behavioral threat assessments for identifying individuals who may be a threat so we can intervene, and anonymous reporting systems like Colorado Safe2Tell also came out of Columbine. And we have continued to focus on creating a positive school climate.

What is Safe2Tell?

In the majority of incidents studied, students were the first to discover another student’s plans for school violence. But when we listened to kids, we also learned that there was a code of silence. We needed a safe way for them to report a concern, so we worked with partners to launch Safe2Tell in 2004.

It’s a way for anyone of any age who has a safety concern to anonymously report it, via an app, the web or even a phone call. It goes to a 24/7 answering point, and they decide whether it should be routed to law enforcement. If it involves a young person, it goes to a school team to follow up. 

It gets over 22,000 calls per year now in Colorado, and there are systems like it all over the country.

What are school shooters like?

People often ask, “What is the typical profile of a school shooter?”, and you really can’t find that in the scientific literature.

What we do know is that attackers almost always exhibit warning signs. You'll often see intense and escalating anger; they'll make threats; there might be an unusual fascination with weapons. They may stop taking care of themselves, have a drop in grades and a change in appearance. Many have had bullying in their lives, and a recent study showed that 68% of mass shootings had in some way been related to domestic violence.

Some of these behaviors, of course, are common. But studies have shown mass shooters tend to have five or more.

What does intervention look like?

Ideally, if a student is acting out and actually does make a threat, a team of people—including a school administrator, someone from mental health, and a school resource officer—will use a process to assess and then manage the threat. One of the best things we can do during the management process is to ensure student gets connected to pro-social healthy adults and healthy activities they love. The last thing you want to do is isolate them even more.

What, if anything, has changed about these incidents?

What’s different is social media. We have seen a 1900% increase in mass casualty extremist plots since the 1990s, and I do think social media has contributed to this increase. When people are feeling disconnected and angry and starting to form a grievance about something, they can now go to online communities and surround themselves with like-minded people who are fostering hate.

What do we need to do now?

Just like we have roads and bridges that we put money toward, we need to be building an infrastructure of violence prevention that supports programs throughout the life-course, from supporting first-time mothers in high-risk situations to providing social and emotional learning in elementary school to providing life skills in high school.

We also need to educate people on the warning signs for violence and what to do if they encounter safety concerns. Unfortunately, crumbs are going into that investment right now. With all the violence in our society, we should be putting billions of dollars in.

We hear a lot about shootings that happened. Are they ever averted?

Yes. There’s actually an averted school violence database that we can learn lessons from. For example, there was one situation where a student was taking photos of different parts of the school as if he wanted to plan an attack; a custodian saw that happening and reported that concern, and law enforcement was able to address the situation, and no attack occurred.

This kind of thing happens over and over again, but we don’t often hear about it.

You’ve been at this for decades. What keeps you hopeful?

Twenty-five years after Columbine, so many groups have come together to identify what works. We know from research that if we were to put these programs that have randomized studies behind them in place we could reduce violence by more than 30%. No question.

I work with too many people who have lost loved ones to violence, and you know what they say? They wish more than anything that it could have been prevented. We can prevent violence, and I’ll spend the rest of my life working toward this goal.