A 69-year-old man was gunned down Thursday afternoon in a busy Kmart parking lot in Tempe during a possible carjacking or robbery attempt, police said.

Praful Patel, a Canadian resident who was staying with his son in Chandler, was shot once in the upper body during a confrontation after four young men surrounded his silver Volvo, Tempe police said.

"It was a brutal murder in broad daylight," said Sgt. Dan Masters, a Tempe police spokesman.

"It appears to be a random act of violence."

The shooting occurred at 1:40 p.m. in the busy parking lot at 1330 W. Baseline Road, just east of Arizona Mills Mall. Several people witnessed the shooting and identified some of the suspects, Masters said.

Witnesses performed cardiopulmonary resuscitation on Patel and reported that he was still breathing shortly after the shooting, police said, but he was pronounced dead when he arrived at Maricopa Medical Center.Patel, whose car was registered in another family member's name in Chandler, had dropped off his wife and grandson to do some shopping and parked under a tree for shade on a hot afternoon, Masters said.

A crisis intervention team was sent to help his family, who discovered the shooting when they came out of the store.

Police detained three men unidentified suspects shortly after the shooting and were questioning them Thursday night, Masters said. Two of the suspects were juveniles, while the third suspect's age was not released.

Masters said witnesses reported that the men briefly jumped into a green or blue car shortly after the shooting, but then got out and fled on foot as the car sped away. A fourth suspect and the alleged getaway driver remained at large late Thursday.

Authorities detained another man they initially believed to be connected to the shooting, but detectives released him Thursday night after an interview.

There were no bullet holes in the Volvo's windshield and it was unclear how the suspects obtained access to Patel. Police have yet to recover the gun used to shoot Patel, Masters said.