A top aide to former President Joe Biden testified behind closed doors for more than four hours on Tuesday as part of the House Oversight Committee’s investigation into his mental fitness to serve and the White House’s use of an autopen, confirming she was authorized to use the automatic signature device while denying allegations of manipulation or malfeasance.

Neera Tanden, head of the White House Domestic Policy Council, revealed in her opening comments Tuesday that she was given permission to use the autopen.

Tanden stated that she “was responsible for handling the flow of documents to and from the president” and was permitted to direct the usage of autopens from October 2021 to May 2023 while acting as Biden’s staff secretary and senior adviser.

Tanden, on her way out after hours of questioning, which included a lunch break, stated she was cooperative.

“I was very happy to answer questions. I answered the questions,” Tanden responded to the Washington Examiner, adding that she was “happy to discuss my public service.”

When reporters pressed Tanden again as she was leaving the Capitol Hill building to ask if there was a cover-up of Biden’s physical condition, she responded, “Absolutely not.”

Tanden is the first of many witnesses expected to testify this week, including Anthony Bernal, a top advisor to former First Lady Jill Biden, who is due to speak with investigators on Thursday.

House Oversight Committee Chairman James Comer (R-KY) told the Washington Examiner on Tuesday morning that the committee wants to know “who was calling the shots” during Biden’s final two years in office, as well as why the president’s signature was increasingly replaced by the use of an autopen to sign certain executive orders, even on days when he was physically present at the White House.

Former President Joe Biden recently doubled down on his usage of an autopen, claiming that he had control of the White House throughout his tenure.

Alleging that senior officials concealed the former president’s cognitive impairment using autopen signings, President Donald Trump requested an investigation into Biden’s administration.

“I made the decisions about the pardons, executive orders, legislation, and proclamations. Any suggestion that I didn’t is ridiculous and false,” Biden saidin a statement.