Latest ratings figures for May indicate that CNN's The Situation Room made strong gains against Fox News's The Big Story. Among adults 18-49, Room, hosted by Wolf Blitzer, was just 6,000 viewers behind Story. The program generated considerable news coverage Tuesday when Samir Sumaidaie, the new Iraqi ambassador to the U.S., told Blitzer that a U.S. Marine shot and killed his cousin. He called the official explanation of the killing -- that the marine acted in self-defense -- "totally unbelievable." Sumaidaie said that he has asked for a further investigation of the killing. His remarks came during an interview in which Blitzer questioned the ambassador about allegations that Marines had massacred Iraqi civilians in Haditha last November and had then attempted to cover it up. Sumaidaie said that before seeing video of the slaughter he had concluded that the allegations were "incredible."