The arrangement drew new scrutiny this week after Cassidy Hutchinson, a former aide in his White House, made an explosive appearance before the House panel, providing damning new details about Mr. Trump’s actions and statements on the day of the deadly riot.

She did so after firing a lawyer who had been recommended to her by two of Mr. Trump’s former aides and paid for by his political action committee, and hiring new counsel. Under the representation of the new lawyer, Jody Hunt, Ms. Hutchinson sat for a fourth interview with the committee in which she divulged more revelations and agreed to come forward publicly to testify to them.

It is not known whether Ms. Hutchinson’s change in counsel led directly to her willingness to appear at a televised hearing and provide a more detailed, wide-ranging account of what she witnessed, but some members of the panel believe that it played a role, according to two people familiar with the committee’s work…

The episode raised questions about whether Mr. Trump and his allies may, implicitly or explicitly, be pressuring witnesses to hold back crucial information that might incriminate or cast a negative light on the former president. Mr. Trump and his advisers have been accused before of trying to influence witnesses in past investigations involving him. The committee is known to ask witnesses frequently during closed-door interviews whether anyone has tried to influence their testimony.