Jillian Peterson, Ph.D., is an assistant professor of criminal justice at Hamline University in St. Paul, Minnesota. James Densley, Ph.D., is an associate professor of criminal justice at Metropolitan State University in St Paul. Their work on mass shooters and crisis intervention can be found at The Violence Project . The opinions expressed in this commentary are their own.

(CNN) Mass shootings are becoming increasingly deadly . Our security approach to stopping school shootings is not working. It may even be making things worse.

On Wednesday, we all hung our heads again in disbelief and horror after 17 beautiful young people were killed at their high school -- four more than lost their lives at Columbine, which nearly 20 years later still stands as a cultural touchstone for this kind of violence.

Since the Virginia Tech massacre in 2007, school safety departments have been tasked with developing emergency response plans for mass violence like this. By all standards, Marjory Stoneman Douglas High School was prepared . Florida is one of 33 states that requires schools to have a plan for active shooters. This large Parkland high school held regular active shooting drills and staff trainings -- in fact, a drill had been held just last month.

It's possible that prior drills prevented additional casualties on Valentine's Day -- with many teachers following protocol and locking themselves in their classrooms with their students.

It's equally plausible that prior drills increased the number of casualties this week -- since Nikolas Cruz , the suspect in custody and a student at Marjory Stoneman Douglas High School for several years, would have been through Run-Hide-Fight style routines numerous times.

Recent studies have demonstrated that active shooter drills may increase anxiety and fear among students, as well as contribute to a negative school culture, which is a risk factor for school violence. Active shooter drills can also trigger a fascination with such events in vulnerable students. In Florida this week, active shooter drills may have even trained the shooter how to carry out his attack more effectively.

It certainly appears Cruz took his understanding of the trained response into account when planning his attack. He pulled the fire alarm , which unlocked the usually locked school doors, and made the school's lockdown procedures difficult to implement. He reportedly stood outside the school to shoot at his classmates as they left the building, and then chased them back inside once they realized what was happening.

We have to do more in our schools than rehearse for inevitable violence and hope to minimize the number of people who die. We need to first prevent before we first respond. We need to walk before we run. The FBI said in a statement Friday that the agency failed to act on a tip about Cruz, so it's clear there are no easy answers here, only many questions about what prevention could look like.

Recently, we have been building a mass shooter database of 135 mass shooters, coded on 50 life history variables like family background and mental illness, to be used to create a more complex understanding of mass violence.

We are using records to find information about perpetrators' mental health, access to treatment, family history, social media use, weapon access, trauma and more. While we are still in the process of analyzing the data, our preliminary results show that the road to violence is often a long one, involving complex, interacting risk factors that develop over time. Our analysis also suggests some potential opportunities -- beyond safety drills conducted in a vacuum -- to intervene and save lives.

Our data indicates that before mass violence takes place, there is typically an immediate trigger in the perpetrator's life. Crisis intervention training, which teaches how to calm someone experiencing a crisis, could be an equally key component of violence prevention. Teaching students, faculty, and staff how to recognize and respond to someone in a crisis, by connecting them to available resources, such as low-cost treatment, can stop a potentially fatal incident from occurring.

Talking more frankly about suicide is also important. Our findings also show that the majority of mass shooters are suicidal -- often taking their own lives after killing others. Therefore, a suicide awareness and prevention approach could also help reduce violence.

Schools must create opportunities for every child to form meaningful relationships with adults that lead to a sense of belonging, and for every child to have confidence that teachers care for them as individuals. Talking to young people about warning signs, risk factors and effective intervention strategies for suicide is imperative. Broad training in suicide prevention can't hurt, considering that the majority of gun deaths in this country are suicides , and suicides among young people are on the rise

Many of the shooters in our study also "leaked" their plans prior to carrying them out. Cruz discussed school shootings with multiple classmates, and posted about his plans on social media . In response to the Florida shooting, President Trump tweeted, "Neighbors and classmates knew he was a big problem. Must always report such instances to authorities, again and again!"

But to whom do you report? And then to whom do they report? Who is responsible for intervening? And what does intervention look like? Who is responsible for repeatedly following up over time? Schools need additional resources for counselors and social workers with the mandate and expertise to assess mental health and promote continuous social and emotional growth.

Follow CNN Opinion Join us on Twitter and Facebook

Schools also need better strategies for integrating vulnerable students into the school. Research on the school-to-prison pipeline shows that expulsion from school rarely solves a disciplinary problem. Was Wednesday's shooting revenge for Cruz's expulsion? That's certainly a possibility, and highlights the need for less punitive, more restorative practices in schools. Conflict resolution and character education, including empathy training for children at young ages to prevent bullying, especially on social media , may further prevent young people from becoming vulnerable in the first place.

One common "solution" touted by pundits and politicians did not appear in our data or analysis. And a case this month where a third-grader discharged a police officer's holstered gun inside a school gymnasium demonstrates further: more guns in schools is also not a solution.

It's time for a new approach.