A grenade was lobbed into the Quetta city police station on Monday, injuring a police official, police sources said. Unidentified miscreants lobbed the grenade into the police station from the southern flank of the compound, the sources said. Policeman Wali Daad was injured and the windows of five vehicles parked in the compound were shattered by the explosion, they said. By Monday evening it had been determined that a homemade grenade had been used, the police sources added.In a separate incident, Agricultural Research Institute Principal Bashir Baloch was shot and critically injured by unidentified attackers. He was taken to Bolan Medical Complex, where he was reported to be in critical condition.