Rarely is there a single trigger that prompts someone to grab a gun and begin shooting strangers, said Frank Farley, a psychologist at Temple University in Philadelphia. It may take time to understand what prompted Sulejman Talovic to walk through a downtown mall and shoot at patrons.

"It's always a recipe," he said, "and it involves a lot of ingredients." In some cases, there may be psychological problems that may or not be diagnosed. A history of problems at home - alcohol and/or violence - can also contribute to what pushes someone to the edge, he said.

Adding to the challenge in piecing together a reason for this crime is that Talovic was 18, an age at which people are transitioning into adulthood.

"Legally, he is an adult," said Paul Ragan, a psychiatrist at Vanderbilt University, in Nashville, Tenn. "But he is psychologically not an adult." Being a refugee, along with his family from Bosnia, can add another level of stress in transitioning to adulthood. Language and cultural barriers can contribute problems. He may have experienced problems creating a social support network.

"How well does a Bosnian national adolescent fit into Salt Lake City culture?" Ragan wondered. "Did he get caught in some kind of gap where he felt he didn't belong?" While it may take time to unravel the circumstances behind the crime, the way it was committed offers clues into the mind of the shooter, said Michael King, a retired profiler who used to work for the Ogden Police Department.

It is likely that Talovic was looking to make a statement by picking a public place and firing at seemingly random people.

"We don't need him to tell us he wants to shoot 'em up and make a name for himself," King said.

The reason behind the shooting spree may be found through talking to family and friends. Talovic may have dropped clues leading up to his actions, King suggested.

From the trench coat, which could have concealed his weapons initially, and the extra ammunition, these facts speak to the planned nature of the attack.

Farley added it is likely that Talovic knew how he would meet his end - in a gun battle with law enforcement.

"Was this a suicide by police?" he asked.