Ian Sams, who was a White House spokesman and senior communications aide to former President Joe Biden, arrived Thursday morning on Capitol Hill for a closed-door, voluntary interview with the House Oversight Committee as part of its investigation into the Biden administration’s use of the autopen.

Sams, who was special assistant to the president and senior adviser in the White House Counsel’s Office, declined to answer reporters’ questions as he entered the Rayburn House Office Building shortly before 9 a.m. He is among a larger list of former senior Biden aides summoned to testify as Republican lawmakers probe whether White House officials usurped executive authority from the former president amid concerns over his mental and physical decline.