The House select committee investigating the Capitol attack formally asked the Republican House minority leader, Kevin McCarthy, on Wednesday to cooperate with its inquiry into the January 6 insurrection, escalating the pressure on Donald Trump’s top allies in Congress. The committee said in a letter to McCarthy that the panel is seeking details about his conversations with the Trump White House and the former president in the days leading up to and during the Capitol attack, as well as discussions in its aftermath. “We also must learn about how the President’s plans for January 6th came together, and all the other ways he attempted to alter the results of the election,” Congressman Bennie Thompson, the chairman of the select committee, said in the letter. Thompson said that McCarthy is of particular interest to investigators as he spoke to Trump directly as the former president’s supporters stormed the Capitol to stop the certification of Joe Biden’s election win. The committee’s request to McCarthy marks a significant political moment for the investigation, as it seeks to ratchet up its inquiry into the Capitol attack with testimony from the highest-ranking member of Congress pursued to date by the panel. Thompson said in the letter that the committee is, in the first instance, interested in McCarthy’s phone call to Trump on January 6 during which he unsuccessfully begged the former president to call off the pro-Trump mob as it stormed the Capitol in his name. According to an account of that call presented at Trump’s second impeachment last year, the former president sided with the rioters and in refusing to take action, told McCarthy that they were evidently more upset about the election than the House Republican leader. “You have acknowledged speaking directly with the former President while the violence was underway on January 6,” Thompson said. “This information bears directly on President Trump’s state of mind during the January 6 attack as the violence was underway.” Thompson said that the committee is also seeking details about McCarthy’s conversations with Trump and Trump’s former White House chief of staff Mark Meadows before January 6, suggesting an inquiry into what McCarthy knew of plans to stop Biden’s certification. “We also must learn about how the president’s plans for January 6 came together,” Thompson said in the letter. “You reportedly explained to Mark Meadows and the former president that objections to the certification of the electoral votes on January 6 ‘was doomed to fail.’” The Guardian first reported last week that the committee has in its possession messages turned over by Meadows and others suggesting the Trump White House coordinated with Republican lawmakers to stop Biden’s certification, according to sources familiar with the matter. Thompson said that the committee is also interested in McCarthy’s communications with Trump in the week after the Capitol attack, including the possibility that Trump could face a censure resolution, impeachment and removal under the 25th amendment. The chairman also revealed for the first time that the select committee has contemporaneous messages showing McCarthy talked to Trump about his immediate resignation, among a number of other potential consequences he may have faced for inciting the Capitol attack.