The district attorney leading a criminal case against Donald Trump and his allies in Georgia accused Rep. Jim Jordan of Ohio of trying to obstruct her prosecution of the case in a sharply worded letter she sent Thursday.

Soon after the district attorney, Fani T. Willis, a Democrat, announced last month that she was bringing a racketeering case against Trump and 18 other defendants for their efforts to overturn the results of the 2020 presidential election in Georgia, Jordan, a Republican and chair of the House Judiciary Committee, said that he was going to investigate Willis over whether her prosecution of Trump was politically motivated.

In her letter, Willis accused Jordan of trying “to obstruct a Georgia criminal proceeding and to advance outrageous partisan misrepresentations,” and of not understanding how the state’s racketeering law works.

“Your attempt to invoke congressional authority to intrude upon and interfere with an active criminal case in Georgia is flagrantly at odds with the Constitution,” she added. “The defendants in this case have been charged under state law with committing state crimes. There is absolutely no support for Congress purporting to second guess or somehow supervise an ongoing Georgia criminal investigation and prosecution.”

The letter came as the defendants and the prosecution continued sparring in legal filings over where and when the trial would take place. In a new filing, Mark Meadows, a defendant, who served as the White House chief of staff under Trump, was seeking a stay of the proceedings in state court until a judge ruled on his motion to move his case to federal court.

The Georgia case is one of four criminal indictments that have been brought against Trump this year; Jordan’s investigation of Willis is the latest example of House Republicans using their power in Congress to try to derail efforts to prosecute the former president.

When he announced his inquiry last month, Jordan, a close Trump ally, said it would look for any evidence of communication between Willis and the Biden administration and examine her office’s use of federal grant money.

While Jordan expressed concerns that former federal officials were being unfairly targeted in a state prosecution, some of the issues he raised had little to do with the underlying facts of the investigation. For example, in a letter to Willis, he said her new campaign website had included a reference to a New York Times article that mentioned the Trump investigation.

Willis’ response is the latest sign that she will not take attacks on her office and the investigation quietly.

She has a track record as a pugnacious, law-and-order prosecutor, and is pursuing racketeering cases not only against the former president and his allies, but also a number of high-profile Atlanta rappers accused of operating a criminal gang.

In a heated email exchange in July over the terms of Gov. Brian Kemp, a Republican, providing testimony in her investigation, Willis called the governor’s lawyer, Brian McEvoy, “wrong and confused” and “rude,” after McEvoy expressed frustration over mixed signals he said he had received from her office and asserted that there had been “leaks” associated with her investigation.

“You have taken my kindness as weakness,” she wrote, adding: “Despite your disdain this investigation continues and will not be derailed by anyone’s antics.”

On Thursday, scores of Trump supporters gathered near the state Capitol for a news conference and rally, demanding that the state legislature call a special session to defund Willis’ office. The effort, led by Colton Moore, a freshman state senator, has little support among Moore’s fellow lawmakers and is almost certain to fail.

Moore, who has drawn attention and praise in recent weeks from news outlets supportive of Trump, said that Willis was engaged in “politicization” of the justice system. His constituents, he said, “don’t want their tax dollars funding this type of corrupt government power.”

In her letter to Jordan, Willis invited him to purchase a book about racketeering statutes written by one her fellow prosecutors on the Trump case, John Floyd, titled “RICO State by State.”