A man with a shotgun ran into Trolley Square and fired multiple shots, killing five people and hitting multiple other victims before he was killed Monday night, police said.

Salt Lake City Police Detective Robin Snyder confirmed the shooter was dead. She said there was only one gunman on the premises and that there were "multiple victims," with at least six fatalities, including the shooter. Several people were in critical condition at area hospitals.

Snyder said significant manpower was necessary to clear out the entire mall, which she said was difficult because of the intricate and old-fashioned design of the building.

Nearly three hours after the mayhem began, Snyder said police were still getting phone calls from people who were hiding in closets and fitting rooms inside the mall.

"There's a lot of scared people inside who want to get out," she said.

Numerous police and fire officials responded to the mall, at 700 E. 500 South, just after 6:45 p.m., hunting a male reported to be "actively shooting" inside the mall, according to Salt Lake City police dispatchers.

Witnesses heard several loud "pops" and "bangs" and ran for cover in stores, bathrooms, hallways and in a restaurant's freezer.

Brad Merrill was waiting with his son outside of the Spaghetti Factory when a shooter ran up the stairs and "blew the doors and windows off."

"He didn't say anything, he just shot in the door," Merrill said. Merrill ran inside the restaurant and yelled, "There's a guy with a gun!" Several people inside called 911.

Merrill's wife and other young children were inside another store at the time, and they were separated for over a half-hour. All of them were "pretty shaken up," he said.

At least two victims were taken to University Hospital in critical condition, and several others were being treated at the scene. Shoppers and employees at the mall were evacuated from the area as officials attended to the various injured and frightened people there, according to Salt Lake City Fire Assistant Battalion Chief Dennis McKone.

An off-duty Ogden police officer was in the mall at the time and fired his weapon at the shooter, killing him, according to Barrett Dodds, an antique-shop owner who witnessed the event.

Ogden Police Sgt. Blaine Clifford confirmed there was an off-duty police officer involved in the mall shooting. "I don't know what level of involvement he had."

Dodds said the shooter was about 6 feet tall, wearing a long trench coat and a backpack, and that he stopped to reload his weapon several times while inside the mall. Dodds said he heard as many as 20 shots fired, and he believed the man was "putting the gun to his shoulder and aiming at people."