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.

In exclusive footage posted by the House Oversight Committee Wednesday evening, O’Connor invoked his constitutional right against self-incrimination at least 15 times, according to a 20-minute video excerpt, as committee investigators pressed him on his past assessments of the president’s mental and physical condition.