Manhattan District Attorney Alvin Bragg filed a lawsuit on Tuesday against Rep. Jim Jordan (R-OH) in an effort to prevent Jordan from questioning a former prosecutor about Bragg’s case against former President Trump.

The lawsuit seeks to block House Judiciary Committee chairman Jordan from following through on a subpoena he issued to Mark Pomerantz, a former special assistant in the Manhattan district attorney’s office who quit when Bragg took over after leftwing billionaire financier George Soros bankrolled Bragg’s campaign.

It also aims more broadly to “put an end to this constitutionally destructive fishing expedition,” in reference to Jordan’s overarching investigation of Bragg.

Bragg, according to a memorandum with the filing, is not only looking to stop Jordan “from enforcing this unlawful and unconstitutional subpoena” by obtaining a temporary restraining order, but also “to prohibit Mr. Pomerantz from complying with it.”

“Their latest salvo—the subpoena to Mr. Pomerantz—is an abuse of congressional process and a brazen incursion into New York’s exercise of its sovereign prosecutorial powers,” it stated.

Jordan condemned Bragg’s latest legal action in a statement online, saying, “First they indict a president for no crime. Then, they sue to block congressional oversight when we ask questions about the federal funds they say they used to do it.” Jordan’s committee likewise issued a statement online, claiming Bragg was “scared” of oversight.

The lawsuit against a sitting congressman marks an escalation in an already heated back-and-forth between Bragg and Jordan, who have exchanged contentious letters about congressional Republicans’ desire to probe what they view as a political, rather than sincere, prosecution of Trump.