Congratulations to long time (going all the way back to beta days) Open Salon member Dave Cullen for being chosen for tonight's PBS News-Hour segment on the Aurora, CO tragedy. As many of you know, Dave is the author of the acclaimed book Columbine which he spent a decade researching and writing.

It's too early to add a link to the video on the PBS site as they don't have that up yet (I'll include it here when it becomes available including the transcript). Meanwhile, here's a shot of Dave I took with my camera.

Some parallels were drawn between the Columbine shooters and the Aurora mass murderer. James Alan Fox, Ph.D and Professor of Criminology, Law and Public Policy of Northeastern University was the other panelist in the segment and there was agreement on many points between Dave and Professor Fox.

The following video and transcript are from the PBS News-Hour web site:

The first part of the video is an interview with Peter Banda of The Associated Press and then the segment with Dave and Professor Fox begins at six minutes and thirty seconds.

Watch James Holmes Arraigned on 142 Charges on PBS. See more from PBS NewsHour.

GWEN IFILL: So is the alleged shooter, James Holmes, a typical or an atypical suspect in cases like these?

For that, we turn to a researcher and a criminologist who have studied other mass shootings.

James Alan Fox is professor of criminology, law and public policy at Northeastern University. He's written widely on the topic, including in his book "Extreme Killing." And Dave Cullen is the author of "Columbine," the bestselling book about 1999's deadly Littleton, Colo., high school shooting.

Welcome to you both, gentlemen.

Dave Cullen, I want to start with you. We think of the names Eric Harris and Dylan Klebold, and even at Virginia Tech, Seung-Hui Cho, and we think to ourselves, these are typical of what mass killers do and now allegedly James Holmes? What is the profile?

DAVE CULLEN, author of "Columbine": Well, it's interesting what you said, that these are typical and whether there's a profile, because there is no single profile. That's for sure.

But between the three of them, oddly enough, we have the three different profiles, because nearly all of these mass murderers turn out to be one of those three profiles. Eric Harris was a psychopath in the clinical sense, meaning no empathy, no remorse, no feeling for others. Dylan Klebold at Columbine was a deep-suicidally depressed kid. And Cho was delusional, out of touch with reality, deeply mentally ill.

Nearly all killers fall into one of those categories, but the three categories are completely different. And if you want to understand their thought process and how they get to murder completely, you have got to separate them into those groups, because they're completely different.

GWEN IFILL: Professor Fox, one of the things that came out of watching James Holmes last week in court is that people thought he was either insane or medicated or very clever in his behavior in court. Are we assuming too much? Are people racing too fast to try to understand this?

JAMES ALAN FOX, Northeastern University: Probably.

Most mass murderers kill people they know for particular reasons, very selective. This is the rarest form of mass murderer, who kills at random. And it could either be someone who is deeply schizophrenic and psychotic, who believes that everyone in the world is evil and has to be punished, which would imply psychosis, or it could be someone who is indeed just trying to show how powerful they are, how superior they are and went through a tremendous amount of planning to get to that end.

We don't know for sure. We may never know, actually. But one thing is clear, that in a case like this, the insanity defense is really a Hail Mary. It's the only option the defense has. But just like his eyes, open and shut, I would say that this prosecution, too, would be open and shut.

GWEN IFILL: Dave Cullen, is there a triggering event that usually brings this on, whether or not you're delusional or psychotic or just severely, suicidally depressed? Is there something that needs to flick that switch?

DAVE CULLEN: Not really. And usually the term we hear a lot is snap. How did he snap or when did he snap?

And that's really the kind of terminology that I think leads us astray, because it's not sort of a flipping a switch. It's not an off-on thing. It's a gradual evolution, which usually goes on for months or even years. Most of them plan in advance, but it takes years before that.

Now, given all that and the sort of slow downward spiral that they normally go through, there can be sort of a final element. And in most cases of mass murderers -- there was a great study on the school shooters in particular done by the Secret Service, where they found that 98 percent of them, you know, a staggering 98 percent had suffered what they considered either a major failure or loss in the time leading up to it.

So there usually is something. Think of that more as a final straw or someone that continues down the path, much more so than something that then set it in motion.

(CROSSTALK)

GWEN IFILL: Professor Fox, one of the things we always start to ask ourselves when these things happen is, is there something we should have seen? Are there signs that we should have been watching for? What do you say to that?

JAMES ALAN FOX: Sure. In the aftermath -- in the aftermath, all those warning signs become crystal-clear, when hindsight is 20/20.

They're really not red flags. They're yellow flags that only turn red once the blood has spilled upon them. The problem is that there's a very large pool of individuals in this country, thousands upon thousands, who are frustrated and angry and disappointed, who blame other people for their problems, who are socially isolated and don't have lots of friends nearby or family nearby to help them get through the hard times, and have access to guns.

The good news, I guess, is that very, very few of them will ever take action. And we really have no way to predict. We -- the characteristics are very predictable, but the identity of these perpetrators are not until after the fact. And let me add one other thing...

GWEN IFILL: Mm-hmm.

JAMES ALAN FOX: ... that Dave Cullen explained very well.  

Younger shooters, the school shooters and even the alleged gunman in Colorado, being 24, are very different than actually the typical mass murderer, who is older. Mass murderers tend to be actually in their 30s and 40s. So the school shooter shares certain characteristics with mass killers generally, but not -- but they really in a certain way are a little bit atypical of the mass murderer, who is very deliberate, who has a history of frustration over years, and kills to punish others for the -- all the troubles that they have had over their lifetime.

GWEN IFILL: Let me ask you both. Another thing that typically arose in a lot of people's conversations right after this happened a few weeks ago is that this is on the rise, that it seems like it's always happening.

And that's what I'm going to ask you both, Dave Cullen, starting with you. Is this typical now? Is this unique to the United States? Is this something that we should worry about in that context?

DAVE CULLEN: Well, it's definitely not unique to the United States.

We have had, you know, horrific cases recently in Germany, in Norway and several different countries. It is more prevalent here. The professor probably has better data than I do on whether these are on the rise or not. But I have seen a lot of conflicting information on that.

GWEN IFILL: What about that, Professor?

JAMES ALAN FOX: No, they're not on the rise.

We have had in this country about two dozen mass murders each year. Most of them aren't to this extreme. But we do have every year about two dozen homicides with four or more victims killed. It hasn't changed over the past 35 years. I have data virtually on all of these cases.

And there are times when we see flurries of cases. In the '80s, we had the postal shootings. In the '90s, we had the school shootings. We have had restaurant shootings. We have the shootings at health clubs. There's no pattern up or down. But I agree that we in the United States have far more than other countries.

We don't have a monopoly on mass murder, but we certainly have cornered the market. But then again, our homicide rate is much higher as well. And part of it is just symptomatic of the violence in our society generally.

GWEN IFILL: And, finally, I want to ask you, Dave Cullen, very quickly, one of the conclusions you reached in your Columbine investigation is that almost everything we heard in the first few weeks turned out not to be true.

DAVE CULLEN: Yes, it did.

I mean, most people think they know the basics about Columbine, that we know that there were these two loner, outcast goths who were part of the trench coat mafia who were bullied relentlessly by jocks and then did this as a huge revenge against the jocks and targeted the jocks.

None of that is true. And that was all a mythology which began as speculation in the media by people like us during the first few days. And it very quickly crystallized into fact and was believed. And that's the danger we need to not repeat this time.

GWEN IFILL: We have to be very cautious of whatever we're reporting and interpreting in the next several weeks. Thank you both very much.

On our website, you can find a link to a photo gallery of images related to the shootings captured by The Denver Post, as well as our own coverage archive.