The congressional committee probing the January 6, 2021, attack on the US Capitol issued subpoenas on Tuesday to three lawyers who joined former president Donald Trump's unsuccessful attempt to overturn his election defeat: Rudy Giuliani, Sidney Powell and Jenna Ellis.
The House Select Committee demanded the pro-Trump lawyers hand over documents and sit for depositions on February 8.
Bennie Thompson, the committee's chairman, said in a statement that the panel expects the lawyers to join the nearly 400 witnesses who have already spoken with the committee as part of its investigation into the causes of the deadly attack by Trump supporters.
The committee also subpoenaed Boris Epshteyn, a Trump political adviser.
Mr Giuliani, Ms Powell, Mr Epshteyn and Ms Ellis did not immediately respond to requests for comment.
“The four individuals we’ve subpoenaed today advanced unsupported theories about election fraud, pushed efforts to overturn the election results, or were in direct contact with the former president about attempts to stop the counting of electoral votes,” Mr Thompson said in the statement.
Ms Powell, Mr Giuliani, and Ms Ellis jointly spoke at a Trump campaign news conference on November 19, 2020, during which they vowed to overturn President Joe Biden's election victory.
Ms Powell promised to “release the Kraken”, likening their effort to a mythological sea monster.
The Trump campaign distanced itself from Ms Powell after she claimed, without evidence, at the news conference that electronic voting systems had switched millions of ballots from Mr Trump to Mr Biden.
Mr Giuliani's New York law license was suspended in June, after a state appeals court found he made “demonstrably false and misleading” statements that widespread voter fraud had undermined the election.
The committee is aiming to release an interim report in the summer and a final report in the autumn on the attack, a source familiar with the investigation said last month.
The committee's members have said they will consider passing along evidence of criminal conduct by Mr Trump to the US Justice Department. Such a move, known as a criminal referral, would be largely symbolic but would increase the political pressure on Attorney General Merrick Garland to charge the former president.