 At that point, the sniper snapped a picture of him 26 minutes before the shooting occurred and radioed the command center. Crooks briefly disappeared, returning moments later with a backpack. The sniper called for backup, but by the time officers responded, the gunman was already positioned on the roof. Next thing you know, I seen like, I thought it was a backpack or something, and then I seen what I knew was a gun, a machine gun.