WASHINGTON — The House committee is considering the January 6 attack on the Capitol on Wednesday has formally requested an interview with Rep. Kevin McCarthy taking the unusual step of calling the minority leader, who was in close contact with former President Donald J. Trump before, during and after the violence and fought to end all investigation of the events.

The public request sent a clear message that the committee’s investigators, including two former U.S. attorneys, are prepared to prosecute even the most senior figures on Capitol Hill as they seek information about Mr. Trump As the violence unfolded, what a federal judge suggested will be key in determining whether Mr. Trump can face any responsibility for the day’s chaos.

He staged a politically charged showdown between House Democrats investigating the assault and Mr. McCarthy, the California Republican who is set to become House Speaker if Republicans retake the chamber in November. And it suggested investigators believe Mr. McCarthy, who admitted speaking on the phone with Mr. Trump as rioters stormed the Capitol, may also have been involved in later conversations about guilt. of the then president in the aggression and what should be done about it.

In a letter On Wednesday, Rep. Bennie Thompson, a Mississippi Democrat and committee chair, said the panel had obtained “contemporary text messages from multiple witnesses” referring to White House staffers expressing “significant concerns” about “the ‘Mr. Trump’s state of mind’. and his conduct continues” in the days following January 6.

“It appears that you have also discussed with President Trump the possibility that he may face a no-confidence resolution, impeachment or removal under the 25th Amendment,” Mr. Thompson wrote to Mr. McCarthy, referring to the part of the Constitution that allows a president to be removed from office if it is determined that he is unable to do his job. “It also appears that you have identified other possible options, including the immediate resignation of President Trump.”

Mr. McCarthy did not immediately respond to a request for comment. But he led his party’s opposition to the formation of a bipartisan panel to investigate the riot, opposed the creation of the committee and attacked the panel’s work for weeks.

This made it unlikely that he would agree to appear for an interview – although he told a California news station in December that he “wouldn’t be hiding anything” – and raised questions about whether the panel would issue a subpoena in an attempt to compel him to testify, or hold him in contempt of Congress if he refused to comply . The moves would represent a major escalation in the battle over the inquiry, which most Republicans have called a partisan exercise designed to tarnish Mr. Trump and his party.

The committee has proposed to meet with Mr. McCarthy on February 3 or 4. He is the most senior lawmaker the group has sued in its investigation.

In September, the committee included Mr McCarthy on a list of hundreds of people whose records it asked social media and telecommunications companies to keep for possible use in the investigation. Mr McCarthy’s spokesman, Mark Bednar, criticized the panel at the time as “politically motivated” and called its request “an overbearing and unconstitutional attempt to dig into individuals’ call logs”.

In the days following the mob attack, Mr McCarthy struck a different tone. He first condemned the violence and said Mr Trump “bears responsibility” for the violence.

“What we saw last week was not the American way,” Mr. McCarthy said on the floor of the House. “The rhetoric continues that Joe Biden is not the rightful president either.”

But Mr. McCarthy eventually changed his stance, re-embracing Mr. Trump – who remains popular among the Republican base – and visiting him at his Mar-a-Lago club in Palm Beach, Florida, towards the end of January.

“Your public statements regarding Jan. 6 have changed significantly since you met with Trump,” Mr. Thompson wrote in his letter. “At this meeting, or at any other time, did President Trump or his representatives discuss or suggest what you should say publicly?

In a recent interview, Rep. Liz Cheney, a Republican from Wyoming and vice chair of the committee, called the Mar-a-Lago meeting a turning point for Mr. McCarthy. He would later lead his party’s efforts to oust him from his leadership position for continuing to vocally call out Mr. Trump, his campaign lies and the complicity of many Republicans in spreading them. And after initially saying he would support a bipartisan investigation into the Jan. 6 attack, he backtracked and vehemently opposed any congressional investigation.

“Looking back, by the time Chief McCarthy visited Mar-a-Lago towards the end of January, the path he had chosen was quite clear,” Ms Cheney said. “He was one who was unfaithful to the Constitution. I believe we have a duty to our oath of office that requires you to put this above politics.

The letter to Mr McCarthy is the committee’s latest attempt to learn more about Mr Trump’s actions as rioters marauded the building for hours on January 6 and his state of mind in the days that followed. .

In particular, the panel said it was interested in a phone call Mr. McCarthy had with Mr. Trump during the riot. Mr. McCarthy previously described the call, in which he asked Mr. Trump to send help to the Capitol, as “very passionate.”

During that call, according to an account given last year during the impeachment proceedings, Mr. Trump sided with the rioters, telling Mr. McCarthy that they were clearly more upset about the election than Republican leader.

The committee also quoted a Politico article reporting that Mr. McCarthy disclosed to other Republicans that Mr. Trump had admitted some responsibility for the Jan. 6 attack during his one-on-one conversations with Mr. McCarthy.

The committee interviewed more than 340 witnesses, including former White House aides. On Wednesday, Kayleigh McEnany, White House press secretary under Mr. Trump, appeared before the committee for a virtual interview, according to a person familiar with the matter.

The request to meet Mr. McCarthy is the third time the committee has asked a Republican lawmaker to voluntarily accept an interview. Representatives Scott Perry of Pennsylvania and Jim Jordan of Ohio refused to cooperate with the panel.

Mr Jordan – who in November told the Rules Committee he had “nothing to hide” – denounced the panel’s investigation Sunday and called the interview request an “unprecedented and inappropriate request.”

Mr Perry, who is close to Mr Jordan, last month declined a voluntary meeting with the committee, calling the panel “illegitimate”.

To date, the committee has been reluctant to issue subpoenas for sitting members of Congress, citing the deference and respect chamber lawmakers are expected to show. But Mr. Thompson has pledged to take such action if necessary.