(This post has been updated)
An off-duty security guard was shot in the head late Wednesday night at a Sunoco station at 38th Street and Girard Avenue.
Lt. John Walker of Southwest Detectives said the guard entered the gas station to buy brake fluid and tried to intervene when he saw a man arguing with a Sunoco cashier about 11:30 p.m.
The man turned around and shot the guard in the head and may have taken the victim's cell phone before fleeing in a green minivan.
The victim, whose name was not released, was admitted in critical but stable condition to the Hospital of the University of Pennsylvania. Walker said the victim was alert and talking.
Tipsters can call 215-686-3183 or 3184.