The move was an effort by the Democratic-led House to bring in a key member of Donald Trump's staff who had direct knowledge of President Donald Trump's efforts to undermine the Russia probe, CNN reported, citing an anonymous source.
Nadler authorized subpoenas earlier this month for McGahn and four other White House officials as part of a probe into possible obstruction of justice, corruption and abuse of power charges, according to CNN.
The House Judiciary Chair issued a statement on the subpoena on Twitter Monday evening.
"Following the scheduled testimony of Attorney General William Barr on May 2, 2019, and the expected testimony of Special Counsel Robert Mueller, which we have requested, the Committee has now asked for documents from Mr. McGahn by May 7, and to hear from him in public on May 21," the statement said. "Mr. McGahn is a critical witness to many of the alleged instances of obstruction of justice and other misconduct described int he Mueller report. His testimony will help shed further light on the President's attacks on the rule of law, and his attempts to cover up those actions by lying to the American people and requesting others to do the same."
The subpoena from the House Judiciary Committee can be read below: