A top aide to former first lady Jill Biden refused to answer GOP investigators' questions on Wednesday as the House Oversight Committee probes whether senior ex-White House aides covered up signs of former President Joe Biden's mental decline.

Anthony Bernal, former assistant to the president and senior advisor to the first lady, was compelled for a July 16 closed-door deposition after missing a previously agreed-upon interview date late last month.

His scheduled sit-down came and went quickly, however. Bernal apparently pleaded the Fifth Amendment to the questions asked by House staffers, a source familiar told Fox News Digital.