Witnesses. Reporter the early report tell us that the bart Police Officer discharge his weapon while responding to an argument across the street. At 4 41 pm a call came in for shots fired. Police are talking to witnesses and pouring over Surveillance Video as they try to determine how it unfolded. The chaos played out at 4 41 pm wednesday night stubs from the bart station. A Police Officer in full uniform responded to gunfire and discharged his weapon. Two men were left injured. One dead and another in serious condition. It is not clear who fired the fatal shot. This area directly over my shoulder. At seventh and chester there was an officer involved shooting. Reporter the bart officer was at the location where a witness said two men were exchanging words. It was an argument between two guys. It turned into a shooting. Reporter where did it start . Right here by the barbershop. Reporter the argument quickly escalated. One of them shot my friend in the lake and the police shot and kille