Manhattan district attorney Alvin Bragg on Tuesday sued Republican congressman Jim Jordan to stop what Bragg called an “unconstitutional attack” on the ongoing criminal prosecution of former US president Donald Trump in New York. The lawsuit aims to block a subpoena of Mark Pomerantz, a former prosecutor who had led the Manhattan district attorney’s investigation of Trump. The subpoena, issued last week by the House of Representatives judiciary committee, which Jordan chairs, seeks Pomerantz’s appearance before the committee for a deposition. Trump pleaded not guilty last week to charges brought by Bragg’s office of falsifying business records to conceal a hush money payment made ahead of the 2016 election. The funds allegedly were used to buy adult film star Stormy Daniels’s silence about an affair she said she had with Trump, which the former president denies. Bragg, a Democrat, accused congressional Republicans of an “incursion” into a state criminal case. “Members of Congress are not free to invade New York’s sovereign authority for their or Mr Trump’s political aims,” Bragg’s office wrote in the lawsuit, accusing Jordan of searching for a pretext for “hauling Mr Pomerantz to Washington for a retaliatory political circus”. Pomerantz left his job at the district attorney’s office shortly after Bragg took over in early 2022, when the new DA declined to pursue an indictment of Trump based on a sprawling probe of his business practices. Earlier this year, Pomerantz published a book criticizing Bragg’s decision not to pursue those charges. He also said prosecutors had previously examined potential charges against Trump over the hush money payments, but were concerned the case would rest on a novel legal theory that may not hold up in court. In announcing the subpoena of Pomerantz last week, Jordan said Pomerantz’s public statements showed that Bragg’s prosecution of Trump was politically motivated. Bragg has said Pomerantz’s case was not ready. “If he wishes to argue that his prosecution is ‘politically motivated,’ he is free to raise that concern to the New York state criminal court,” Bragg’s office wrote in the lawsuit. “Chairman Jordan is not, however, free to unconstitutionally deploy Congress’s limited subpoena power for raw political retaliation, intimidation, or obstruction,” it added. The judiciary committee said on Monday it would hold a field hearing next week in New York about what it called “an increase in violent crime” caused by Bragg’s policies. Bragg said murder, shooting, burglary and robbery rates were all lower in Manhattan so far this year compared with last year. On Tuesday afternoon, Jordan, who represents Ohio, tweeted: “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.”