SALT LAKE CITY — An unarmed man shot while attempting a carjacking outside a Utah grocery store over the weekend had prior convictions for robbery and assault and was already being sought by police when a bystander killed him.

Police said Monday that 26-year-old Taulagi Matafeo of Springville was shot once in the chest Saturday after he lunged for a gun pointed by a 31-year-old Orem man who intervened in the carjacking about 40 miles south of Salt Lake City.

Officers and prosecutors are still investigating but do not expect charges to be filed against the shooter because he was acting in self-defense, said Orem police Lt. Craig Martinez.

Investigators said he intervened to help a woman screaming after Matafeo got inside her running car in Orem and struggled with her as she was half-outside of the vehicle. The shooter told Matafeo to get out of the car and put his hands up.

Martinez said it initially looked like Matafeo was going to comply, but then he lunged for the gun and was shot.

For privacy reasons, police do not plan to release the shooter’s name or the car owner’s identity.