Some politics think that The White House counsel, Donald F. McGahn II, has cooperated extensively in the special counsel investigation, sharing details about how President Trump obstructed justice.
Mr. McGahn provided the investigators a clear view of some president’s moments with his lawyer. His cooperation began in part as a result of a decision by Mr. Trump to collaborate fully with Mr. Mueller.
(From Pres. Trump Twitter account 6:12 PM - Aug 18, 2018: "I allowed White House Counsel Don McGahn, and all other requested members of the White House Staff, to fully cooperate with the Special Counsel. In addition we readily gave over one million pages of documents. Most transparent in history. No Collusion, No Obstruction. Witch Hunt!"
Meanwhile, the White House press secretary Sarah Huckabee Sanders, said in a statement that the president and Don have a great relationship.