The House select committee investigating the Jan. 6 Capitol riot has sent a letter to Republican lawmaker Scott Perry (R-PA), requesting his “voluntary cooperation” with its probe, the panel’s chairman announced Monday. The move, which stops short of subpoenaing the representative, marks the first known effort by the panel to speak to a sitting member of Congress about the events surrounding the Capitol insurrection. In a press release, Chairman Bennie G. Thompson (D-MS) said that the committee had received information from multiple witnesses “tying Rep. Perry” to Jan. 6, including evidence proving “his involvement in efforts to install former Department of Justice official Jeffrey Clark as acting Attorney General.”

Perry, the incoming chairman of the far-right Freedom Caucus, has emerged as one of Trump’s staunchest allies on Capitol Hill, following reports that he aided Trump’s efforts to pressure the Department of Justice into overturning the election. Perry reportedly introduced Clark, a mid-level Justice official, to the former president. Clark, who did not end up being named as acting Attorney General, would go on to indicate that he supported Trump’s baseless claims of election fraud. In the committee’s letter, Thompson also cites evidence of Perry’s “multiple text and other communications” with Mark Meadows, Trump’s former chief of staff, “regarding Mr. Clark.”