According to financial disclosures, in May alone, Mr. Trump’s “Save America” political action committee paid about $200,000 to law firms. That including $75,000 to JPRowley Law, which represents Cleta Mitchell, a pro-Trump lawyer who has filed suit to try to block the committee’s subpoena, and $50,000 to Silverman, Thompson, Slutkin & White, which has represented Stephen K. Bannon, a close ally of the former president who refused to meet with the panel and has been charged with criminal contempt.

It was not immediately clear whether those payments were for covering legal fees connected to the Jan. 6 inquiry, but people familiar with the matter said the PAC has paid for the representation of several former officials and aides in the investigation, including some high-profile ones such as Stephen Miller, who served as a senior adviser to Mr. Trump. The managing partner at the firm representing Mr. Bannon declined to comment.

A spokesman for Mr. Trump also declined to comment.

More than a dozen witnesses before the Jan. 6 committee have also received free legal advice and had attorney’s fees paid for by the American Conservative Union’s “First Amendment Fund,” which consults with Mr. Trump’s team about whose fees to cover from its “seven-figure” finances, according to Matt Schlapp, the organization’s chairman.

“We have pro bono lawyers who talk with the lawyers for the people who want help,” Mr. Schlapp said in an interview on Thursday. “Almost everybody has received payment.”

He said Matt Whitaker, a former acting attorney general, was working with the group and has “spent a lot of late nights counseling younger staffers and giving us a lot of advice.”

Mr. Trump has come under scrutiny before for appearing to meddle in inquiries into his conduct. In 2017, a lawyer for Mr. Trump in the investigation into whether his campaign conspired with Russian officials during the 2016 presidential campaign dangled the prospect of pardons to two people under investigation, Michael T. Flynn and Paul Manafort.