A police officer was killed and three others injured on Monday by a bomb in western Afghanistan, an official said. "Gul Ahmad, the district police chief of Charsada in Ghor province, was killed and three other police officers were injured when a bomb detonated close to his vehicle this morning," provincial spokesman Abdul Hay Khatibi said. He said the bomb was strapped to a donkey and remotely detonated, according to a report of DPA. He blamed the Taliban for the attack.