British police say they have launched a full investigation into the disappearance of Madeleine McCann, and want to trace 38 "persons of interest" in the case. Detectives say it's possible that Madeleine, who vanished from a Portuguese holiday resort six years ago, is still alive. Scotland Yard said today that 12 of the individuals of interest are British, and the rest from a variety of European countries. The force says it is working with governments across the continent to find out more. (Portugal has so far refused to reopen the case.)