The House select committee investigating the Jan. 6 riot requested Wednesday to interview House Minority Leader Kevin McCarthy (R-Calif.) about his communications with former President Donald Trump and ex-Chief of Staff Mark Meadows before, during, and after the Capitol attack, The Washington Post reports. McCarthy is the highest-ranking elected official the committee has asked to speak to, Axios notes.

In a letter to the lawmaker, committee Chairman Rep. Bennie G. Thompson (D-Miss.) said details of McCarthy’s conversations with the former president and Meadows “could provide the committee with further insight into Trump’s state of mind at the time,” writes the Post.

“We also must learn about how the President’s plans for Jan. 6th came together, and all the other ways he attempted to alter the results of the election,” Thompson wrote to McCarthy. “For example, in advance of Jan. 6th, you reportedly explained to Mark Meadows and the former President that objections to the certification of the electoral votes on Jan. 6th ‘was doomed to fail.'”

Among other things, the chairman also asked the minority leader about reports that McCarthy himself had encouraged Trump to stop the riot as it was happening, notes CNBC.

The committee had previously requested information from two other GOP House lawmakers, Reps. Jim Jordan (Ohio) and Scott Perry (Pa.), both of whom declined to cooperate, per CNBC.

Thompson said Wednesday the committee thinks McCarthy will “voluntarily come forward,” though a subpoena is on the table should he decline to do so.