The chairman of the U.S. House Judiciary Committee has sent a letter to District Attorney Fani Willis demanding records and documents related to any communication she had with federal officials related to her investigation of former President Donald Trump and his allies.

Rep. Jim Jordan, an Ohio Republican, said that he wants to find out whether Willis coordinated with the Department of Justice or the Biden White House as she led an inquiry into whether Trump and others broke the law when they attempted to overturn the results of the 2020 election.

Jordan wrote in Thursday’s letter that he questions the motivations of Willis’ investigation and the timing of the grand jury’s charges now that the 2024 presidential contest is underway. He also characterized the investigation as possibly infringing on the free speech and other constitutional rights of Trump and other defendants.

“When states rely on acts like these—apparently taken in connection with official duties— to criminally prosecute federal officers, it raises serious concerns under the Supremacy Clause of the Constitution and poses a threat to the operations of the federal government,” he wrote.

CNN was the first to report on the Judiciary investigation.

Jordan gives Willis a deadline of 10 a.m. on Sept. 7 to provide all information about federal funding received by her office, documents or communications with the Justice Department and particularly Special Counsel Jack Smith and any documents or communications with the White House regarding the investigation of Trump or 18 other codefendants.

The letter comes hours before Trump is expected to turn himself in at the Fulton County jail to face 13 charges, including an allegation that he led a criminal enterprise focused on stealing the election.

Jordan is among Trump’s most prominent defenders in Congress and has endorsed him in the 2024 presidential race.