U.S. prosecutors believe fifa President Sepp Blatter's top lieutenant made $10 million (£6.6 million) in bank transactions that are central to the Bribery investigation of the world football body, a source familiar with the matter said on Monday.Jerome Valcke, fifa's secretary general, is described in an indictment filed in federal court in Brooklyn, New York, as an unidentified "high-ranking fifa official" who in 2008 transferred the sum to another fifa official, Jack Warner.Valcke is not named as a defendant and has not been accused of any wrongdoing. He was not immediately available for comment.