President Joe Biden’s White House physician is refusing to answer questions as part of the House Republican investigation into Biden’s health in office.

The House Oversight Committee has requested interviews with several of Biden's former White House aides in light of a reports questioning his mental fitness in his final year in office and alleged efforts by those around him to conceal it -- allegations Biden has vehemently denied.

Former President Joe Biden’s personal physician, Dr. Kevin O’Connor, repeatedly invoked the Fifth Amendment during a closed-door deposition on Wednesday. He refused to answer whether he was ever instructed to lie about Biden’s health or whether he believed the president was unfit for office.