conducting a transaction with an unidentified man. here he removes what appears to be a gun from his pocket followed by money from the same pocket. within seconds, sterling is seen jokingly making a shooting motion toward the man. that night police were initially called to the triple-s convenience store responding to a 911 call from a witness who saw a man with a gun. watch closely as things escalate quickly. from salamoni's perspective, you can see a brief struggle, then his gun is trained on sterling's head. >> don't you [ bleep ]. i'll shoot you in your [ bleep ] head, you hear me? don't you [ bleep ] move -- >> all right, hold up. hold up. you're hurting my arm. >> narrator: sterling was pinned to the ground and tased twice. >> get on the ground! get on the ground! >> pop him again, howie! >> reporter: before being fatally shot. previously released cell phone videos recorded by bystanders show at this point in the encounter salamoni believed sterling was armed. >> he's got a gun!