Lawyers for the House panel investigating the Jan. 6, 2021 attack on the Capitol said in a court filing Wednesday that former president Donald Trump and key allies engaged in potential crimes during their effort to overturn the election: conspiring to defraud the United States and obstructing an official congressional proceeding — the counting of electoral votes.

The alleged criminal acts were raised by the committee in a California federal court filing challenging conservative lawyer John Eastman’s refusal to turn over thousands of emails the panel has requested related to his role in trying to persuade Vice President Mike Pence to reject electors from states won by Joe Biden. Eastman has cited attorney-client privilege as a shield against turning over the documents because he has said he was representing Trump at the time.

The committee argued in its filing that Eastman’s claim of privilege was potentially voided by the “crime/fraud exception” to the confidentiality usually accorded attorneys and their clients, which holds that communications need not be kept confidential if an attorney is found to be assisting their client in the commission of a crime. They asked the judge deciding whether to release Eastman’s emails to privately review evidence the committee has so far gathered to see if he believes it establishes that Eastman was assisting Trump in criminal acts.

“The Select Committee also has a good-faith basis for concluding that the President and members of his Campaign engaged in a criminal conspiracy to defraud the United States,” according to the filing.

The court filing is the strongest assertion yet from the committee that it believes Trump and some of his allies potentially committed crimes during the effort to overturn Biden’s victory and by falsely stating repeatedly that the election was stolen.