SAN DIEGO — Authorities reached out to the public Wednesday for help in identifying a group of men who attacked a 64-year-old RV resident when he confronted them about standing on his vehicle's roof, then stole an item from his pocket as he lay on the ground unconscious on a Kearny Mesa street.

The attack happened around 9:30 p.m. June 28 in the 7100 block of Engineer Road, according to San Diego police.

The victim was inside his RV, which was parked along the road, when a group of street racers arrived in the area for an apparent meet-up. Several vehicles arrived in the area and the drivers began doing "burn-outs" in the street, while other members of the group climbed on top of the man's RV, police said.

When the victim walked outside to confront the group, three men began physically assaulting him, knocking him unconscious. Another man took an unknown item from the victim's pocket as he lay unconscious on the ground, then the group fled in a 2003 Audi A4 sedan, police said.

The victim, whose name was withheld, was taken to a hospital for treatment of major head trauma, including a brain bleed, and a fractured vertebrae, according to police.

Anyone with information about the assault or the identity of the men involved was urged to call the San Diego Police Department's eastern division at 858-495-7957, or San Diego County Crime Stoppers at 888-580-8477.

Tipsters may remain anonymous and could be eligible for a reward up to $1,000.