After Mr. McGahn was initially interviewed by the special counsel’s office in November, Mr. Trump’s lawyers never asked for a complete description of what Mr. McGahn had said, according to a person close to the president.

Mr. McGahn’s lawyer, William A. Burck, gave the president’s lawyers a short overview of the interview but few details, and he did not inform them of what Mr. McGahn said in subsequent interactions with the investigators, according to a person close to Mr. Trump.