Christopher Miller, who was acting secretary of defense during the Jan. 6 riot, met Friday with members of the House Committee investigating the origins of the attack on the Capitol, a source familiar with the panel's activities told NBC News.
The committee is increasing its probe, issuing more subpoenas and requesting several GOP lawmakers to testify.
It wasn't immediately clear what Miller discussed with the panel. The former Pentagon chief has given conflicting testimony to Congress in the past, saying former President Donald Trump had encouraged the protesters with his remarks on Jan. 6 and then later saying he believed an organized conspiracy played a role in the Capitol attack.
In December, the panel met with Kash Patel, who was Miller's chief of staff at the Pentagon and a former top aide to Rep. Jim Jordan, R-Ohio.
The committee has been trying to speak with many Trump allies, former administration officials and Republican lawmakers in recent weeks. Some have complied with subpoenas, while others have said they will not cooperate with the committee.
House Minority Leader Kevin McCarthy, R-Calif., said Wednesday he wont comply with the panel's request for an interview because it is not conducting a legitimate investigation. The Department of Justice brought charges against more than 700 alleged participants in the Jan. 6 riot. More than 100 Capitol Police officers were reported to have been injured in the melee.
Elmer Stewart Rhodes, founder of the far-right militia group The Oath Keepers, was indicted on Thursday for seditious conspiracy and other charges related to the breach of the Capitol, the Justice Department said.