The House select committee investigating the Jan. 6, 2021, insurrection will reportedly hear on Friday from Donald Trump s former National Security Adviser Robert OBrien as lawmakers continue to piece together the ex-presidents actions around the Capitol riot and discussions within his Cabinet to remove him from office.

While OBrien was not a member of the Cabinet, he was said to be involved in the discussions about invoking the 25th Amendment, which would have put then-Vice President Mike Pence in power. OBrien has denied any involvement.

OBrien, who was not in Washington on Jan. 6, remained in his post after the insurrection, while his deputy Matthew Pottinger resigned in the immediate aftermath. Pottinger testified before the committee during a hearing about what the former president was doing while his supporters stormed the Capitol.

OBriens scheduled appearance before the committee was reported by CNN and NBC News .

In recent weeks, the panel reportedly interviewed former Transportation Secretary Elaine Chao, who is married to Senate Minority Leader Mitch McConnell (R-Ky.). It also heard from former Secretary of State Mike Pompeo.

Chao resigned from her post on Jan. 7, 2021, while Pompeo stuck with Trump and criticized those who resigned or sought to otherwise distance themselves from the then-president post-Jan. 6.

Rep. Zoe Lofgren (D-Calif.), a member of the Jan. 6 committee, confirmed Pompeos appearance while speaking to CNN s Situation Room earlier this week.

I think we fill in a few pieces here and there each time we interview someone, Lofgren told CNNs Wolf Blitzer. Obviously, weve had testimony from others about what he said and did. And so, its just a matter of filling out the entire picture, especially on that day and the events subsequent to that day, where the Cabinet secretaries had concerns about the president.

After the insurrection, Democrats pushed for Pence and the Cabinet to remove Trump from office using the 25th Amendment. The amendment would have required approval from the vice president, as well as either a majority of the Cabinet or a Congressionally-appointed review body.

Pence announced days after the insurrection that he would not invoke the 25th Amendment.

Cassidy Hutchinson, a former aide to then-White House chief of staff Mark Meadows, has testified Pompeo informed Meadows of those discussions within the Cabinet.

The Jan. 6 committee has also interviewed, among others, former Treasury Secretary Steve Mnuchin , former acting Attorney General Jeffrey Rosen and former Labor Secretary Eugene Scalia.

CNN reported the committee is currently discussing a potential testimony with former Education Secretary Betsy DeVos.

While the committee has no more public hearings scheduled for now, it continues to garner evidence as part of its probe.

This week, a lawyer for two Sandy Hook parents suing conspiracy theorist Alex Jones turned over more than two years of his text messages to the panel.