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

Rep. Jim Jordan, an Ohio Republican, said he wants to find out whether Willis coordinated with the Department of Justice or the 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.

The Fulton district attorney’s office said it had no immediate comment on Jordan’s letter. CNN was the first to report on the Judiciary investigation.

U.S. Rep. Marjorie Taylor Greene, who said earlier this week that she had spoken to House GOP leaders about investigating Willis, was among the first to applaud the Judiciary probe. The Rome Republican wrote on X, the site formerly known as Twitter, that she was “proud” of Jordan.

“We need to look deeply into the coordination of efforts between (President Joe) Biden’s DOJ and State DA’s,” Greene said.

Jordan gave Willis a deadline of 10 a.m. 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 co-defendants.

The letter came hours before Trump was 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 and Greene are among Trump’s most prominent defenders in Congress and have endorsed him in the 2024 presidential race.