White House Counsel Don McGahn will be interviewed by investigators connected with Special Counsel Robert Mueller's Russia probe some time in the next few weeks, CNBC learned Monday.
The interview, which was first reported by CNN, has not yet been scheduled, according to a lawyer close to the case.
As the White House counsel, McGahn has been a key player in a number of events at the heart of the ongoing investigations into the president and his top advisors, including the resignation of Michael Flynn as national security adviser and the president's firing of former FBI director James Comey.
McGahn was present in a meeting in which former acting Attorney General Sally Yates told White House officials that the Russians "knew that General Flynn had misled the vice president and others," according to Yates' May testimony in front of the Senate Judiciary committee.
Flynn later resigned after only 24 days, the shortest ever tenure for a national security adviser.
McGahn was also on hand during the president's decision making process ahead of the firing of James Comey.
After Trump wrote an "angry, meandering" letter explaining his reasoning for firing the FBI director, McGahn convinced the president not to publish it, according to The New York Times.
That letter, the Times wrote, has since become a significant element of Mueller's investigation.
A lawyer for the president, Ty Cobb, did not respond to CNBC's request for comment, but has disputed accounts that the letter was incriminating and has called it "wholly exonerating."
McGahn is still waiting on guidance from Cobb on whether the president will invoke executive privilege or attorney-client privilege, according to the lawyer close to the investigation. Invoking either would limit how much information McGahn could provide to the special counsel.
An attorney for McGahn declined to make him available to CNBC. Cobb did not respond to CNBC's request for comment.