Mass murderers often not mentally ill, but seeking revenge, experts say Those who commit mass murders are often angry and isolated, but usually aren't mentally ill, violence experts said Friday after a shooting during the midnight screening of "The Dark Knight Rises" in an Aurora, Colo., movie theater. James Holmes was arrested as a suspect in the shooting that killed 12 people and wounded 59 others. "It takes a certain degree of clear-headedness to plan and execute a crime like this," said James Alan Fox, a criminal justice professor at Northeastern University in Boston, who has written several books on mass murder and school violence. There are exceptions - Jared Loughner, who shot and killed six people in Arizona in 2011, gravely injuring then-member of Congress Gabrielle Giffords, was diagnosed with schizophrenia. Mental health experts say people with mental illness are not any more likely than anyone else to become violent, however. Mass murderers "often times feel that they are right and everybody else is wrong," Fox said in a telephone interview. They really tend to externalize blame, to see other people as responsible for their problems. They are often socially isolated. "They tend to be a failure at life," Fox added. 12 dead, 59 injured in Colorado movie theater shooting Such well-planned attacks are rare and not meant to make a statement, Fox said. "They basically want revenge," he said. Contrary to the common misperception that these guys suddenly snap and go berserk, these are well-planned executions. The film the victims were watching is loaded with violence but it's unlikely that actually inspired the attacker, Fox said. The film was opening that night and it's doubtful the attacker was familiar with the script. "It was just coincidental, although it just made the situation more ambiguous for the people involved," he said. Some of those who were in the theater said they initially first thought the shooting was part of the screening. Early reports suggest Holmes did not have a police record and the University of Colorado has confirmed he was in the process of dropping out of a Ph.D. program in neuroscience there. Former FBI profiler Clint van Zandt told TODAY that Holmes was almost certainly acting alone. "Today, so far, he appears to be ... the lone wolf," Van Zandt said. The attack was carefully planned, both Van Zandt and Fox said, which fits the patterns of such attackers. "They typically plan carefully how they are going to do it, where they are going to do it, what they are going to bring and what they are going to wear," Fox said. In this case, the victims were not deliberately chosen, although the place, a packed movie theater, probably was. The attack may encourage copycat actions but not necessarily, Fox said. "What bothers me in situations like this is to see lists of the worst mass shootings," he said. It encourages people to try to break records. Dr. Victor Schwartz, medical director of the Jed Foundation, which works to promote mental health among college students, agreed. "The media needs to be really careful in these situations," he said. On the one hand, you need to report the story. On the other hand, there is the danger of sensationalizing it, almost romanticizing the drama here. Schwartz also advises resisting any attempts to speculate on whether violent videos or movies may have affected Holmes. "The research slants both ways," he said. Some studies suggest that children who watch and play violent videos may become desensitized to some aspects of violence, but there is not a clear consensus. "None of these things is caused by a single factor," Schwartz said. Obviously, these are always very complicated events. The impulse is to find a simple explanation for complicated situations. It is important to resist it. Experts say it's almost impossible to predict attacks like this one. "Neighbors will come forward and say it was no surprise," Fox said. But it's all after the fact. Beforehand, even though someone may fit a profile, we can't predict they will do this sort of crime. It's a very rare event and not predictable. That's part of what makes it so scary. Former FBI profiler Clint Van Zandt speaks with TODAY's Matt Lauer again, calling the Colorado movie theater shooter a "lone wolf," which he says is "the thing the FBI director and others are most worried about."