An Iraqi journalist was gunned down on his way to work Saturday, becoming at least the fifth media figure killed since an outbreak of sectarian violence after the bombing late last month of a Shiite shrine north of Baghdad. Iraqi police, meanwhile, said an American aid worker taken hostage with three other peace activists was apparently tortured before he was shot in the head and chest and his body dumped near a railroad line in Baghdad. There was no immediate word on his fellow captives, a Briton and two Canadians. Amjad Hameed, a journalist for Iraqiya television, was attacked by gunmen who shot him in the head and chest while he was being driven to his job. His driver, Anwar Turki, died later in the hospital. Iraqiya is run by Iraq's Shiite-dominated government and seen by minority Sunni Muslims as biased against them.