Former White House official involved in 'unmasking' controversy joining Justice Department A controversial former NSC official is joining the Department of Justice.

Ezra Cohen-Watnick, a former White House adviser and Trump loyalist, will be joining the Justice Department as a national security adviser to Attorney General Jeff Sessions, a source familiar with the move confirms to ABC News.

His appointment to the upper echelon of the Justice Department comes as President Donald Trump has been publicly lambasting the DOJ and FBI over how fast it's complying with congressional Republican requests for documents and records related to the FBI's investigation of Hillary Clinton, FISA applications seeking surveillance of Trump associates, and the Russia probe generally.

Trump has alleged that the department is slow-walking the request and has something to hide. Some Republican allies of the president have suggested a vote to hold top DOJ officials in contempt of Congress.

As ABC reported in March 2017, Cohen-Watnick was one of two White House officials who played a role in surfacing the classified 'unmasking' documents viewed by House Intelligence Committee Chairman Devin Nunes. At the time, Nunes described the information as potential evidence of improper surveillance by U.S. spy agencies working under the Obama administration.

On Fox News Tuesday night, Nunes, who gave the DOJ and FBI until Wednesday to comply with a records request, said, "We will have a plan to hold in contempt and impeach" Deputy Attorney General Rod Rosenstein and FBI Director Christopher Wray.

"We're not messing around here," Nunes said.

It's not clear what Cohen-Watnick's role will be at DOJ and there is no indication that it's directly related to the document production controversy. Cohen-Watnick did not immediately respond to requests for comment from ABC News.

Cohen-Watnick was brought into the National Security Council by former national security adviser Mike Flynn after serving as Flynn's aide in the Defense Intelligence Agency. Flynn's successor, H.R. McMaster, ousted him last August, saying at the time that Cohen-Watnick would serve "in another position in the administration."

Cohen-Watnick instead went on to join the tech software company Oracle under CEO Safra Catz, a frequent guest of President Trump in meetings with technology leaders. Cohen-Watnick is expected to join the DOJ under Sessions as soon as next week, the source confirmed to ABC News.