Former Trump campaign manager Paul Manafort, who appears to be among the primary targets of Robert Mueller’s Russia probe, may also become the first to face charges. According to a new report, Mueller’s team is working with the Manhattan U.S. attorney’s office on a case against Manafort, tied to the F.B.I. investigation into last year’s presidential election.

The U.S. attorney’s office for the Southern District of New York is working in conjunction with Mueller’s team to determine whether Manafort was involved in a money-laundering scheme, The Wall Street Journal reported Tuesday. Sources familiar with the matter told the Journal that the collaboration began after Mueller tapped Andrew Goldstein, who heads the office’s public corruption unit, to join his high-powered team. Assistant U.S. Attorney Paul Monteleoni, who previously served on the money-laundering and asset-forfeiture unit, is also working on the probe, according to sources that spoke with the outlet. (Although a spokesperson for Manafort did not respond to a request for comment from the Journal, Manafort has denied any wrongdoing.)

Manafort’s growing list of legal headaches is an unmistakable sign that Mueller is zeroing in on the political operative, who has long-standing ties to Russian interests. Multiple Congressional committees investigating Kremlin election meddling have requested his testimony, and Mueller—whose focus on Manafort reportedly spans an 11-year period—recently instructed federal prosecutors to raid his home in July. Subpoenas have been issued to a number of Manafort’s associates seeking financial information, including his former son-in-law, Jeffrey Yohai. On Wednesday, Bloomberg reported that Manafort, who is reportedly buried in legal fees, is likely to lose $4 million he sunk into Los Angeles real-estate investments following a bankruptcy hearing. And in August, Mueller teamed up with the office of New York Attorney General Eric Schneiderman.

Mueller’s collaborations with Schneiderman and the Manhattan U.S. attorney’s office are particularly noteworthy, as any charges born out of the investigations would be exempt from presidential pardons—which only apply to federal crimes—raising the possibility that they could be used as leverage against Manafort and, by extension, the Trump campaign.

For his part, Trump seems to have taken an unusual level of interest in candidates for open U.S. attorney positions in Manhattan and Brooklyn—last week, Politico reported that Trump personally interviewed two front-runners for the job, both of whom have ties to Trumpworld. (Geoffrey Berman, a top pick for the Manhattan post, is a partner at the law firm where Trump ally Rudy Giuliani works, and Ed McNally, a front-runner to head the Brooklyn office, is a partner at the firm of Marc Kasowitz, Trump’s longtime personal lawyer.)

While the White House denied that such interviews were unusual, once confirmed, both U.S. attorneys will have jurisdiction over cases involving Trump associates. The head of the Eastern District of New York office, which is based in Brooklyn, would oversee the ongoing probe into Kushner Companies—the real-estate company owned by the family of Trump son-in-law Jared Kushner—over its use of the federal visa program known as EB-5. And the attorney appointed to lead the Southern District of New York would have jurisdiction over the Manafort money-laundering probe.