One of former Vice President Mike Pence’s closest advisers, Marc Short, is going to comply with the House Jan. 6 Select Committee’s subpoena, sources told CNN on Monday.

Short received the subpoena three weeks ago from the House committee continuing to dig into the events of Jan. 6 andf the siege on the U.S. Capitol, according to the report.

He is expected to have firsthand knowledge of Pence’s actions, movements and communications as protesters at the Capitol sought to interrupt Congress’ certification of Joe Biden’s presidential election win. Some protesters were reported to have been chanting to “hang Mike Pence.”

The Jan. 6 committee is getting “significant cooperation with Team Pence,” a source told CNN, which reported Short was willing to cooperate on a “friendly subpoena.”

Short issued a “no comment” when contacted by CNN. The committee also declined to comment to CNN.

Short has a long history working with Pence, including when Pence was a member of Congress, but he also served as former President Donald Trump’s legislative director for the first year and a half of Trump’s administration.

Short was with Pence on Jan. 6 and attended a Jan. 4 Oval Office meeting with Trump and attorney John Eastman. That meeting included a discussion of delaying the certification of the election amid allegations of election fraud raised by the Trump camp, according to CNN.

Trump banned Short from the White House after Jan. 6, according to CNN, as he reportedly sided with Pence’s refusal to submit to Trump’s request to take bold action and probe the fraud claims thoroughly before certifying the election results.