Several people who worked closely with former Vice President Mike Pence are cooperating with the House select committee investigating the Jan. 6 Capitol riot, helping the panel piece together what was happening at the White House that day, Axios reports.

Marc Short, Pence’s former chief of staff, and Alyssa Farah, Pence’s former press secretary, are among those who are speaking with the panel, Axios reports. One person with direct knowledge of the matter said some of the witnesses have testified without a subpoena, and another told Axios that Short would not have cooperated unless Pence gave his approval. Two additional sources said many of the witnesses have only met with the two Republican members of the committee — Rep. Liz Cheney of Wyoming and Rep. Adam Kinzinger of Illinois.

The panel is particularly interested in learning more about what former President Donald Trump was doing during the attack, as he ignored requests from lawmakers and advisors to publicly call off his supporters who stormed the Capitol while lawmakers were certifying the 2020 election results. People with knowledge of the matter told Axios that some of the most helpful information is coming from junior staffers who were at the White House on Jan. 6 and had access to top administration officials.

Farah told Axios that she spoke with the committee more than once last year, and “you could see how much information they already had.” She believes those who aren’t cooperating “are doing so out of complete fealty to Donald Trump and not wanting to piss him off,” and they’ve come to learn that “the committee has quite a bit more information that they realized. And their involvement is known to a much greater degree than they realized.”

In the spring, the committee plans to hold televised hearings to explain to the public what Trump was doing behind the scenes during the Capitol attack.