NEW YORK (AP) - A U.S. Marine shot and killed a wounded and apparently unarmed Iraqi prisoner in a mosque in the former insurgent stronghold of Fallujah, according to dramatic pool television pictures broadcast Monday. A Marine spokesman in Washington said the shooting was under investigation. The shooting Saturday was videotaped by pool correspondent Kevin Sites of NBC television, who said three other previously wounded prisoners in the mosque apparently also had been shot again by the Marines inside the mosque. The incident played out as the Marines 3rd Battalion, 1st Regiment, returned to the unidentified Fallujah mosque Saturday....