MICHEL MARTIN, HOST:

We're going back to the Las Vegas shooting now, and more broadly, the conversations that are being sparked by it. We wanted to take a look at an issue that's getting more attention in research circles, and that is the relationship between mass killings and domestic violence. It's important to note that in the case of the Las Vegas shooter, Stephen Paddock, authorities have not said whether they've homed in on a motive. His live-in partner says she had no inkling of what was planned. But in more than half of mass shootings, 54 percent, the perpetrator also shot an intimate partner or relative, that according to the gun control advocacy group Every Town For Gun Safety.

To talk more about these links and what to make of this, we called Robert Spitzer. He's a professor of political science at State University of New York, SUNY, in Cortland, N.Y. He's written and edited many books about gun control, gun rights and public policy. He's with us now from his home. Professor Spitzer, thanks so much for speaking with us.

ROBERT SPITZER: It's good to be with you.

MARTIN: Let's just start by saying we really don't know definitively if the suspect in the Las Vegas massacre has any history or tendency toward domestic violence at this point, but we do know that the man who shot House Majority Whip Steve Scalise over the summer had been charged with domestic assault. We know that the wife of the Pulse nightclub shooter in Orlando said that she was beaten by him and forbidden from leaving the house. So what do we know about whether there is a link between people who commit domestic violence and people who then go on to commit these mass shootings?

SPITZER: The anecdotal evidence suggests that there is a link to the extent that people who commit mass shootings are acting out through an expression of extreme violence, some kind of rage, some kind of grudge, some kind of anger. And that is also consistent with behavior of those - and again, they're overwhelmingly men, we should point out - who are also disposed towards domestic violence. It's important to point out that people who commit domestic violence, you know, bad though that is, for the most part, do not commit mass acts of violence.

MARTIN: I was going to ask you about that. Is there any way we could dig into this a bit further? And it is hard to trace back just because a lot of the people who then go on to commit these mass shootings themselves die. We can't talk to them about like, what were you thinking? But I do wonder about if there are any clues from anybody who has survived or written letters, or has anybody ever, you know, left any kind of trail that suggests why?

SPITZER: One of the things about mass violence and mass shootings is that they almost never occur spontaneously with no prior indication. That was one of the odd things, frankly, about the Las Vegas shooting, although the investigation is continuing, and there may yet be important information to be uncovered and revealed. But the Las Vegas shooting seems to be an anomaly in the sense that there doesn't seem to be any obvious indication of prior violence, prior misdeeds, prior emotional problems. But if you look at the scope of the cases that we do know about especially, the well-known ones, there certainly is information that was left behind. There is witness testimony by family members, by friends, who have provided, you know, some kind of information, indicate that this person was having particular problems of one kind or another.

MARTIN: You started to talk about this a bit earlier about kind of the thinking of people who do commit acts of domestic violence and how that might translate into a mass shooting. Could you talk just a little bit more about that? Do you - I mean, you may or may not know. What do you think?

SPITZER: These are individuals who have great difficulty in coping in a responsible adult-like way, let's say, with emotional problems, emotional turmoil. They are men who often have very traditional views of male-female relationships. There certainly is a train of behavior that is observed where, for example, children who abuse animals are very likely to grow up to become abusers of human beings in their interactions.

So there are - whether it's biochemical or whether it has to do with upbringing and family dysfunction and other things, there are behaviors and actions and activities that tend to establish a trail of problems. The extreme end point of that trail of problems is people, of course, who commit mass violence, which is a very small percentage of people who have these sorts of problems. But nevertheless, it is a trail that researchers are pursuing.

MARTIN: That is Robert Spitzer. He's a professor of political science and the author of many books on gun policy, gun rights and gun control, including "Guns Across America: Reconciling Gun Rules And Rights." Professor Spitzer, thanks so much for speaking with us. Transcript provided by NPR, Copyright NPR.