Special Counsel Robert Mueller’s team suggested Wednesday that there were other yet-to-be-revealed public relations firms involved in Paul Manafort’s Ukraine lobbying scheme beyond those already referenced specifically in the indictment.

The hint came in a hearing in front of a federal judge in Washington D.C. concerning Manafort’s request for what’s known as a bill of particulars. Manafort is asking the judge to require the prosecutors to give him more details about the charges being brought against him.

Manafort’s attorneys pointed specifically to a line in the indictment referring to alleged unregistered foreign lobbying work done by Company A, Company B, Company C “and others.”

Company A and Company B are Mercury Public Affairs and the Podesta Group respectively, it’s been reported. Company C refers to a PR firm allegedly hired by Manafort to promote a report assembled by the law firm Skadden Arps justifying the imprisonment of the political rival of Manafort’s Ukrainian client.

The prosecutors have confirmed for Manafort’s attorneys those companies’ identities.

Greg Andres, of Mueller’s team, initially told Judge Amy Berman Jackson that the “others” referred to the principals at Company A and B, who he said were working on the Ukraine lobbying campaigns. But towards the end of the hearing, Andres got up to clarify that the “and others” also refers to other PR firms. He said the Manafort’s attorneys had been put on notice that there were other PR firms.

Earlier in the hearing, Andres argued that the prosecutors weren’t legally required to disclose the information that Manafort was seeking at this point in the proceedings. He also said that doing so would prematurely give Manafort a list of the witnesses the government planned to call at trial, though Andres admitted that that was less of a concern for him.

The particular portion of the indictment in question related to the charge that Manafort violated that Foreign Agents Registration Act, which requires that any lobbying done in the U.S. on behalf of a foreign agent be registered with the Justice Department. He also faces charges of money laundering and false statements related to his Ukraine lobbying work, which predated the several months he served as chairman of President Trump’s 2016 campaign. He has pleaded not guilty to those charges, as well as to those brought by Mueller in a separate case in Virginia.

In the lead-up to a grand jury handing down the indictment against Manafort and his business deputy Rick Gates last October, it was reported that the Podesta Group and Mercury has been subpoenaed by Mueller. The Podesta Group has since been shuttered, though it’s unclear whether Mueller plans to bring any charges against the firm, which was led by Democratic lobbyist Tony Podesta, brother of Hillary Clinton campaign chairman John Podesta.

Both groups were hired to lobby on Capitol Hill on behalf of an organization called European Centre for a Modern Ukraine, which Mueller alleges was a front for Ukraine’s pro-Russia Party of Regions.

Corrected: A previous version of this story misattributed a comment made by Mueller prosecutor Greg Andres to Scott Meisler, another member of Mueller’s team. Andres made the remark that “and others” referred to principals at Company A and Company B.