The U.S. intelligence official who “unmasked,” or exposed, the names of multiple private citizens affiliated with the Trump team is someone “very well known, very high up, very senior in the intelligence world,” a source told Fox News on Friday.

Intelligence and House sources with direct knowledge of the disclosure of classified names told Fox News that House Intelligence Committee Chairman Devin Nunes, R-Calif., now knows who is responsible — and that person is not in the FBI.