By Jan Wolfe and Patricia Zengerle

WASHINGTON (Reuters) - The congressional committee investigating the January 6, 2021, attack on the U.S. Capitol on Wednesday said former President Donald Trump may have engaged in criminal conduct in his bid to overturn his election defeat.

According to a committee court filing, "evidence and information available to the Committee establishes a good-faith belief that Mr. Trump and others may have engaged in criminal and/or fraudulent 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," the filing said.

The court document was filed in federal court in Los Angeles as part of the U.S. House of Representative Select Committee's dispute with John Eastman, a lawyer who advised Trump on a plan to invalidate election results in key battleground states.

Eastman sued the committee in December, seeking to block a congressional subpoena requesting that he turn over thousands of emails.

The Select Committee's members have said they will consider passing along evidence of criminal conduct by Trump to the U.S. Justice Department. Such a move, known as a criminal referral, would be largely symbolic but would increase political pressure on Attorney General Merrick Garland to charge the former president.

Representatives of Eastman and Trump did not immediately respond to requests for comment.

The committee's leaders said in a statement that "Eastman’s emails may show that he helped Donald Trump advance a corrupt scheme to obstruct the counting of electoral college ballots and a conspiracy to impede the transfer of power."

Attorney regulators in California said Tuesday they have been investigating Eastman and whether he acted unethically in his work for Trump. The investigation could lead to disciplinary action against Eastman, such as suspension of his law license.

(Reporting by Jan Wolfe and Patricia Zengerle in Washington; Editing by Jacqueline Wong)