A suicide bomber in Peshawar, Pakistan, killed a senior police official who had been involved in numerous operations against militants, police said. The attack Thursday killed Superintendent of Police Abul Kalam Khan as he traveled in his car, and injured four others, including Khan\'s driver, Pakistan\'s Express Tribune reported. \"The bomber had struck the side of the car where Khan was seated,\" police official Rahim Shah told the Tribune. The explosion killed him instantly, the report said. CNN reported Khan\'s anti-militant operations had included fighting the Pakistani Taliban. \"He was instrumental in stopping militants from entering Peshawar city,\" said senior government official Mian Iftikhar Hussain. There was no immediate claim of responsibility for the attack. The Tribune quoted police as saying they suspect the attacker was aware of Khan\'s work routine and was hiding behind a tree, waiting for his vehicle. Khan had been involved in many operations against militants in the violence-hit northwest region of Pakistan close to the border with Afghanistan. \"Kalam Khan was a brave police officer and the prevailing law and order situation is directly connected to the situation in the adjacent tribal belt and neighboring Afghanistan,\" area Minister Bashir Bilour said.