SAN DIEGO — A 40-year-old man was gravely wounded Sunday in a shooting outside a San Diego bar, and investigators implored witnesses to come forward with information about the gunman.

The shooting happened at about 1 a.m. Sunday outside the business on Mission Gorge Road in Grantville, according to Lt. Andra Brown of the San Diego Police Department.

“When officers from Eastern Division arrived on scene, they found a male down in a parking lot with at least one apparent gunshot wound to his upper body,” Brown said.

San Diego Fire-Rescue personnel rushed the man to a hospital, where he underwent surgery, but he was not expected to survive his injuries, the lieutenant said.

Investigators said a large crowd was present at the time of the shooting, and they scattered immediately when police arrived. Detectives would like to speak to them, the lieutenant said.

“We know that there were a lot of people here in the parking lot,” she told OnScene.TV. “So we know that there are people here that know what happened. And we would really like them to come forward with that information. I mean, a man’s life is hanging in the balance.”

Because of the serious nature of the man’s injuries, detectives from the SDPD’s Homicide Unit were called to the scene to investigate.

“It is still early in the investigation and very little is known about the circumstances leading up to the shooting, but detectives have learned that a male wearing a dark shirt walked up to the victim and fired at him before fleeing westbound out of the lot in a dark vehicle,” Brown said.

The victim was identified, but his name was not immediately released.

Anyone with information about the shooting was asked to call the Homicide Unit at 619-531-2293 or Crime Stoppers at 888-580-8477.