Daniel L. Zelenko, a white-collar defense lawyer and former federal prosecutor, said that in all of the potential crimes that were being looked at in connection with Mr. Trump’s conduct, the Justice Department would need to show that he had the intent to commit a crime. Mr. Zelenko said that while the new details revealed by the committee would help prosecutors in proving intent, the government still had a range of other issues to overcome in building any prosecution.

“The key is having contemporaneous evidence that he was saying that he knew the election was not stolen but tried to stay in power anyway,” said Mr. Zelenko, a co-chair of the white-collar defense practice at Crowell & Moring. “The problem with Trump is that you have to try and get inside his mind, and he has such a history of lying and pushing falsehoods that it makes it difficult to determine what he really believes.”

Aside from the evidence the committee has already revealed, the panel has received other testimony that undermines Mr. Trump’s claim that he thought he really won the election. According to two people briefed on the matter, Alyssa Farah Griffin, the White House communications director in the days after the election, recently testified to the committee that Mr. Trump said to her in November 2020 words along the lines of: Can you believe I lost to Mr. Biden?