PITTSBURG (BCN) – Police are investigating the shooting of a 17-year-old boy in the parking lot of a Pittsburg Jack in the Box restaurant early Sunday, police Lt. Brian Addington said.

An employee at the restaurant, located at 2135 Railroad Ave., heard gunfire and reported the shooting at 2:30 a.m.

By the time police arrived, all parties had fled. Officers saw blood on the asphalt but the victim was gone.

The teenager, a Pittsburg resident, later showed up at Kaiser Permanente in Antioch where he was treated for a gunshot wound to his bicep and released.

“The victim was driven to the hospital by his friends,” Addington said.

Investigators believe the shooting was preceded by a heated confrontation between the shooter and the victim, who was accompanied by about four friends, Addington said.

After the exchange, the suspect pulled a handgun out of his gold, four-door sedan and shot the victim in the arm, police said.

Police are still trying to determine what sparked the confrontation.

“We don’t know whether the incident was gang-related, but an investigation is under way,” Addington said.”

The suspect remains at large. Witnesses described him as an approximately 20-year-old black man with dreadlocked hair, wearing a white T-shirt and black shorts.