The determination came in a decision by a federal judge that John Eastman, a lawyer for the former president, had to turn more of his emails over to the House Jan. 6 committee.
John Eastman said in a court filing that he had received handwritten notes from President Donald J. Trump as they strategized about how to keep him in power.
Despite concluding that it has enough evidence, the committee is concerned that making a referral to the Justice Department would backfire by politicizing the investigation into the Capitol riot.
A high-profile ruling about a subpoena from the House committee investigating the Jan. 6 attack turned on a lower standard of proof than a criminal trial.