House Judiciary Chairman Jerrold Nadler (D-NY) on Monday issued a subpoena to former White House Counsel Donald F. McGahn II following “revelations” uncovered during Robert Mueller’s investigation into obstruction of justice by President Donald Trump.

The subpoena calls for “testimony and documents related to the Committee’s ongoing investigation into obstruction of justice, public corruption and other abuses of power by President Trump, his associates and members of his Administration.”

Nadler asserts that McGahn is a critical witness to many of the alleged instances of obstruction of justice and misconduct described in Mueller’s 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.”

Nadler reiterated that while Mueller was unable to reach the judgment that Trump did not commit obstruction of justice, Congress has a “constitutional obligation to hold the President accountable.”