An aide to former President Joe Biden spent Friday on Capitol Hill testifying for hours behind closed doors in the latest interview in the House Oversight Committee’s investigation into Biden’s inner circle and his use of the autopen.

Ashley Williams, a special assistant to the former president and deputy director of Oval Office operations, entered a House office building at 10:45 a.m. and did not take any questions from reporters. She left the interview room around 4:50 p.m. and avoided the press as she went. Her six-hour stint on Capitol Hill included a lunch break and another short recess before wrapping.