Talovic was then killed in a shoot-out with police.

The report revealed Salt Lake City Police Sgt. Andy Oblad fired twice at Talovic after the gunman first fired his shotgun at the officer. Oblad and Hammond faced Talovic together from one direction. From the opposite direction, Sgt. Josh Scharman fired three rounds into Talovic's back and then two more into his chest and one into his head after Talovic turned to face him. Detective Brett Olsen fired five times at Talovic and then twice more when he turned toward him. Detective Dustin Marshall fired another five rounds at Talovic.

Talovic was struck 15 times by police gunfire, the report said. A total of 29 shotgun shells fired by Talovic were recovered at the crime scene.

Mystery

What caused Talovic to commit what the report called, "one of the worst murder incidents in the history of the city," is still unknown.

"None of the people interviewed believed the violent act committed by Sulejman Talovic could have been predicted," the report states.

As has been reported by the Deseret Morning News, Talovic was characterized as a loner who rarely socialized and would not initiate any conversations. Police do not believe the Bosnian immigrant's Muslim faith, terrorism, violent video games or other influences can be attributed as reasons for the massacre. An autopsy found no drugs or alcohol in his system.

The only indication that anyone knew he was going to do something was in a phone call he made the night before to Monika Ibrahimovic, a sort-of girlfriend he had in Amarillo, Texas. The report said he told her "Tomorrow would be the happiest day of his life, but that it could only happen once."

He did not elaborate on what that meant.

Talovic did not yell anything in a foreign language during the killing spree, the report said. The only words officers heard Talovic speak — his final words — were "(expletive) you," which he said in English.

Talovic was wearing a box-shaped locket no bigger than a finger-nail on a chain around his neck when he was killed. A family member told police the locket is called a hamajlija, but detectives do not believe it was a sign that religion was a motivation in the killing spree.

Vickie Walker, whose husband Jeff was killed, and son AJ was wounded, said a lack of motive was not surprising.

"They did the best they could," she said. "I just think he was someone that just didn't fit in and was hurting incredibly deep."

The only information police had about Talovic's mental state was that once he was taken to Salt Lake Regional Hospital to be treated for anxiety when his hands started shaking at work.