SAN DIEGO(AP) This mugger was left holding a bag he didn't really want. Police said they were searching for a gunman who ran up to a woman while she was walking her dog Monday night and grabbed the bag she was holding. It contained poop. When the gunman discovered what was in it, he threw it down in disgust, pointed his gun at the 32-year-old woman and demanded money, San Diego police detective Gary Hassen said. He then aimed his .22-caliber semiautomatic at the dog, named Misty, and pulled the trigger twice but the gun didn't fire, Hassen said. The robber, who was believed to be in his 20s, ran to a waiting small, silver car and fled, police said.