Joe Biden’s White House physician on Wednesday declined to answer questions during a closed-door deposition with the House Oversight Committee, invoking his Fifth Amendment right as the Republican-led panel pushes forward in its probe of the former president’s mental fitness and decline.

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.