Boy Arrested in Killing of Shoplifters’ Pursuer : Crime: Gang members show up at a hospital, thinking one of their own was shot at the Encino store. Their inquiry leads police to the youth.

Los Angeles police Tuesday arrested a 15-year-old gang member they believe was involved in the death of a Woodland Hills man who was shot as he chased three shoplifters from an Encino convenience store.

Detective Rick Swanston said investigators were led to the teen-ager by fellow gang members who turned up at Northridge Hospital Medical Center late Sunday, erroneously thinking that one of their own had been shot. Their inquiry provided the hospital staff and police with the suspect’s first name and the auto license plate numbers of his friends who asked about him. With that information, detectives were able to trace a suspect.

The Van Nuys youth’s mother turned him in to police on Tuesday. He was being held on suspicion of murder at Juvenile Hall in Sylmar, Swanston said.

Swanston added that police were not yet certain whether the arrested youth was the fleeing thief who fatally shot Christopher L. Brown, 24. Police are still seeking two other teen-agers.

Brown, an avid soccer player who hoped to become a police officer, was eating a snack with two friends in the parking lot of a 7-Eleven in the 17000 block of Burbank Boulevard when they noticed three teen-agers run out with 12-packs of beer and realized the market had been robbed.

They chased the trio, and Brown was shot in the chest with a handgun after cornering one of the teen-agers in the back yard of a nearby house.

The three shoplifters might have been immediately identified if a store video camera had been working properly. But when police reviewed the tape, it was so blurred that human figures could not be distinguished, police and an executive with 7-Eleven’s parent company said.

Brown’s father, Dennis, said this week that he and his wife were dismayed that the camera at the 7-Eleven was faulty. He urged convenience store managers to keep video equipment in good condition to help police solve crimes such as the killing of his son.

“It’s really a crime” that his son’s killer was not captured on videotape, he said.

A videotape from a Northridge 7-Eleven recently turned out to be crucial in identifying and arresting a suspect in the hunt for the “needle bandit,” a thief who threatened convenience store clerks with a hypodermic needle that he claimed contained AIDS-tainted blood.