As things quiet down after the shocking mass murders of people at a Salt Lake City shopping mall, observers everywhere are asking themselves one question — what would prompt someone to do something like this?

Until more information emerges about 18-year-old Sulejman Talovic, it is impossible to say, according to Jed Ericksen, associate director of adult services at Valley Mental Health.

"I think if you looked at a dozen different events of this nature, it's entirely possible to find 12 psychologically different individuals and motives," Ericksen said.

"Unless, and until, you really have a lot of facts and history about any particular perpetrator of such an act, it's just conjecture," he said. "Some may have some characteristics in common, but with many different events of this nature, the persons involved have very different experiences, very different motives, very different triggering events. The purpose and objective of what they do can be very different.

"Sometimes these are thought-out and planned; sometimes they are very impulsive kinds of events," Ericksen said.

Talovic was a Bosnian native and was in that country until coming to the United States in 1998. It is possible he witnessed the civil war that raged in that region from 1990-95 and may have been harmed by what he saw, but there is no solid information regarding that right now and that still would not explain everything.

"Obviously, people who go through psychologically traumatic experiences of any kind can be left with emotional wounds, although certainly there are lots of people who have traumas who don't erupt in aggressive attacks on other people," Ericksen said.

When the perpetrator is dead, experts then have to do a psychological autopsy by gathering facts, personal history and enough information to arrive at some answer for what happened.

"That's always a little risky because without a live individual to give you first-hand information, you're always speculating to some degree," Ericksen said.

In general, though, the kinds of people who have committed similar shootings fall into several categories, says University of Utah psychiatry professor David Tomb — classic psychopaths, people who are psychotic, people with impulse control disorders and people who feel marginalized. Add to that, Tomb says, a teenage mind that hasn't matured intellectually.

"They personalize too much, more than most adults. That adds another degree of difficulty in predicting what likely was going on with this boy."