The doctor for former President Joe Biden declined to answer questions during a deposition with the House Committee on Oversight and Accountability, which is investigating whether there was a cover-up regarding Biden’s alleged mental decline.

A source familiar with the testimony told Scripps News that Dr. Kevin O’Connor invoked his Fifth Amendment right during the roughly hour-long session.

Republicans on the committee were quick to criticize the move.

“The American people demand transparency, but Dr. O’Connor would rather conceal the truth,” said Committee Chairman James Comer. “Dr. O’Connor took the Fifth when asked if he was told to lie about President Biden’s health and whether he was fit to be President of the United States.”

Democrats, meanwhile, accused Republicans of engaging in partisan attacks.

“Oversight Republicans could be working to lower costs for American families and conducting oversight of President Trump’s corruption, but instead are obsessed with the past,” said Rep. Robert Garcia, the committee’s ranking member.

Biden’s health became a central issue during the 2024 campaign. He dropped out of the race after a widely criticized debate performance in which he appeared confused, at times, and lost his train of thought.

Biden has said the performance was affected by jet lag and a cold.