San Francisco police have launched a manhunt for a car thief armed with a hand gun stolen from an officer. Authorities say the story began this morning when the thief crashed a stolen car as he was being pursued by police. In a scuffle with one officer, the thief managed to wrestle his gun away and flee. Moments later — he reportedly car-jacked a taxi cab and sped off, only to wreck that car at 10th and Stevenson. He escaped from that wreck with the pistol.