(CNN) Special counsel Robert Mueller's prosecutors revealed Thursday night that they're using information related to the searches of Paul Manafort's belongings for their ongoing investigation, according to documents they filed with the court in his case.

The office even used a warrant from March 9 to get information related to five AT&T phone numbers -- and that search involves information related to "ongoing investigations that are not the subject of either of the current prosecutions involving Manafort," according to the new special counsel filings

Manafort, Trump's former campaign chairman, faces criminal indictments in Virginia and DC federal courts related to his foreign lobbying business from before the campaign. He's pleaded not guilty in both.

But that may not be the extent of the legal trouble for Manafort -- and potentially those around him. His lawyer has suggested in court that prosecutors may be continuing to investigate him. The special counsel's office said earlier this week that the Justice Department has allowed for an investigation into Manafort allegedly colluding with Russians to interfere in the 2016 election, alongside several other unconfirmed investigations.

Last week, Manafort's lawyers sought from Mueller's office unredacted versions of some of the almost two dozen search warrants used in his case, while accusing the prosecutors of "hiding the ball" on executing the searches legally.

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