A pair of St. Paul criminology professors, with the help of a federal grant, have compiled a database on “mass shooters” in America — which they believe to be the most comprehensive in academia to date.

As part of the project, which received $300,000 in funding from, the U.S. Department of Justice, the professors also corresponded with six perpetrators of mass shootings, all currently incarcerated.

The goal, they say, was simple.

“A trace of the pathway of how they got to the point of murder. Start when they were born, up until the point of where they killed someone,” said professor Jillian Peterson, from Hamline University.

“I think we were just getting frustrated at the lack of knowledge and level of discourse on mass shootings,” said professor James Densley, who teaches at Metropolitan State University. “It (the project) starts to challenge the perception these are just individuals beyond comprehension, and that mass shootings are just a way of American life. That crazy people do crazy things — there’s nothing you can do about it. Well there are things you can do about it — things that are worth trying.”

That was their hope, added Peterson.

“When we started this, there just wasn’t good data on anything. Our goal is to put this all together — it’s apolitical. It’s data,” she said. “It can be used by reporters or legislatures, to rely on to say, ‘how can we prevent this from happening again?’ ”

MODERN MASS SHOOTINGS

The database, available for anyone to download online at theviolenceproject.org, includes 171 perpetrators, dating back to 1966.

Why 1966?

That was the date of the first “televised” mass shooting — the Texas Bell Tower shooting at the University of Texas in Austin, in which Charles Whitman killed 15 and injured 31.

“There were previous mass shootings, certainly. But that the first ‘modern’ mass shooting, resembling ones today,” Peterson said.

As for what defines a “mass” shooting, the professors adopted the FBI’s standard, established in the 1980s, defining a “mass killing” as the death of four or more people at one time. The FBI wanted something to differentiate such cases from those involving serial killers.

Both professors admit they have problems with that: such a definition, for example, would exclude the most recent shooting at a Southern California high school, where two people died.

“We would like to expand the definition to include clear attempts (at mass shootings),” Peterson said.

And yes, there have been databases created by journalists, the professors admit. The Washington Post and Mother Jones both built one.

But both focus on the incidents, more than the shooters.

Thus, the professors have, over the past several years, used a small army of assistants to put together 100 pieces of perpetrator history.

There are basic demographic variables: age, education, gender, sexual orientation, race, religion, military service, immigrant status, and any criminal, gang or terrorist affiliation.

And not so basic: Whether they grew up with a single parent. Whether any parents committed suicide. If they’d gone through a recent breakup or employment trouble.

There’s a significant portion on mental health: Whether they’d been hospitalized for mental illness, or prescribed anti-psychotics. Any evidence of suicidal tendencies or substance abuse.

And there’s also a component on the firearms used: whether they were purchased legally, illegally, or stolen. The method of purchases, such as private sales, gun shows or stores.

The two say rather than weigh in on the gun control debate, they want to provide data usable for anyone with a stake in the issue.

“We need to have more data-driven and less emotionally-driven debate on those types of issues,” Densley said.

Still — despite the professors’ focus on the dissemination of facts, rather than the drawing of conclusions — the two point out some data points. The fact that the majority of shooters were suicidal and had experienced a recent “crisis” event like a lost job or breakup.

RESPONSES FROM PERPETRATORS

Not included in the database are the professors’ interviews with remaining living perpetrators across the country.

“We sent letters to every perpetrator still living — most die on scene,” Peterson said. Of the 171, that meant 35 letters.

Seven wrote back.

One, involving a high-profile case, they couldn’t get access to despite a plea to a state governor. Peterson declined to say which one.

When they met with or wrote to the other six, “We said it wasn’t about the crime, but the buildup,” Peterson said.

They’ve also interviewed perpetrators’ families, as well as those of victims. They hope to compile all that — attributed anonymously — into a book.

Added Densley, “No one ever really recovers from a mass shooting. It fractures the social fabric of the community. … We of course recognize that. Our objective is to understand who these people are, to prevent this from happening again.”