The House Judiciary Committee issued a subpoena Monday to former White House Counsel Don McGahn, demanding he testify in public near the end of May. “Mr. McGahn is a critical witness to many of the alleged instances f obstruction of justice and other misconduct described in the Mueller report,” committee chairman Jerry Nadler (D-NY) wrote in a statement. “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 compels McGahn to produce documents related to Michael Flynn’s contacts with Sergey Kislyak, President Trump’s contacts with James Comey, and Jeff Sessions’ recusal from the Mueller investigation, among others, and is part of the committee’s larger investigation into allegations that President Trump attempted to obstruct justice. Just three days earlier, the committee subpoenaed Attorney General William Barr, demanding that he provide the unredacted Mueller report by May 1. McGahn, who played a key role during the first two years of the Trump administration, is called to deliver the documents by May 7, and to testify in public on May 21.