Fani Willis, the district attorney in Georgia's Fulton County, made the allegation in a letter to Representative Jim Jordan, a staunch Trump ally who heads the U.S. House of Representatives' Judiciary Committee, the newspaper reported.
Trump was indicted in Georgia last month on charges including conspiring to overturn his 2020 election loss.
Jordan announced a probe in an Aug. 24 letter to Willis in which he questioned her motivation in bringing the case, requested documents on her office's use of federal funds and asked whether she coordinated with the Justice Department.
In her letter, which the newspaper published on its website, Willis said allegations that the prosecution is politically motivated were "unfounded" and that U.S. constitutional law permits her to ignore his requests.
"(There) is no justification in the Constitution for Congress to interfere with a state criminal matter," Willis wrote.
Representatives for Jordan and Willis did not immediately respond to requests for comment.
Trump, 77, has been criminally charged in four cases this year, two of which were brought by U.S. Special Counsel Jack Smith. He denies wrongdoing and calls the cases politically motivated.
Trump, the first former U.S. president ever to face charges, is the front-runner in the race for the Republican nomination to face President Joe Biden, a Democrat, in the 2024 U.S. election.
(Reporting by Katharine Jackson; Additional reporting by Jasper Ward and David Morgan; Editing by Rami Ayyub and Cynthia Osterman)
By Katharine Jackson
