A federal grand jury is looking into whether Hilton Worldwide should face criminal charges concerning the document-theft civil suit filed last spring by Starwood Hotels & Resorts, according to a report last week in the Wall Street Journal. Following that report, Hilton CEO Christopher Nassetta sent a letter, obtained by USA Today, to all Hilton owners, reassuring them that Hilton is taking the matter very seriously and is cooperating with the U.S. Attorneys' Office in an effort to resolve matters. According to an unnamed source in the WSJ article, Hilton has fired or placed on leave about 30 members of its luxury brands group since Starwood filed the suit. Last month, Hilton named John Vanderslice as head of its luxury and lifestyle division.