State Department official says member of UAE royal family reportedly detained . Investigation continuing after videotape shows sheikh torturing grain merchant . U.S. emerged Saturday in federal civil lawsuit filed in the United States . the United States senior officials say case is holding up a U.S. nuclear deal with the Abu Dhabi .
State Department official says member of Abu Dhabi royal family reportedly detained . Investigation continuing after videotape shows sheikh torturing grain merchant . Videotape emerged last month in federal civil lawsuit filed in the United States . U.S. senior officials say case is holding up a U.S. nuclear deal with the UAE .