Evidence given by prosecutors to the defense team in the ongoing prosecution of a Russian troll farm accused of meddling in the 2016 U.S. presidential election was altered and posted online as part of a “disinformation campaign” to discredit the Russia probe, special counsel Robert Mueller’s team alleged in a court filing Wednesday.

“Certain non-sensitive discovery materials in the defense’s possession appear to have been altered and disseminated as part of a disinformation campaign aimed (apparently) at discrediting ongoing investigations into Russian interference in the U.S. political system,” prosecutors write in the filing.

The allegation comes amid an ongoing dispute in the case against Concord Management over whether the defense team can ferry “sensitive material” obtained during discovery to its client in Russia.

Mueller does not accuse defense counsel of involvement in the document release, but was adamant in insisting that the government’s servers were not breached.

The special counsel alleges that “non-sensitive discovery materials have been misused in a manner inconsistent with the terms of” a protective order that the judge issued in the case.

Specifically, Mueller alleges that discovery provided by the government made its way into a webpage containing more than 300,000 files. That information included “junk material” irrelevant to the case, Facebook memes allegedly produced by the Internet Research Agency, and actual documents provided by the special counsel in the course of the litigation.

A Twitter account with the handle “@HackingRedstone” posted a link to the web portal containing the files in October.

“Enjoy the reading!” the account tweeted.

According to the filing, an unnamed individual also sent a Twitter DM to an unidentified journalist about the information on the same day that HackingRedstone appeared.

That reporter then purportedly alerted the special counsel’s office to the breach. The webpage containing the files was deactivated “after a request from the government,” the filing states.

Mueller alleges that the account that posted the discovery to the online portal can be linked back to Russia.

“A representative of the online file-sharing portal has confirmed to the FBI that the specific account used to publish the matching discovery materials was registered on October 19, 2018 by a user with an IP address that resolves to Russia,” prosecutors allege in a footnote.

The special counsel describes being advised of the issue by Concord’s lawyers on the day after HackingRedstone published the link.

“Defense counsel advised that the vendor hired by the defense reported no unauthorized access to the non-sensitive discovery,” prosecutors write. “Defense counsel concluded, ‘I think it is a scam peddling the stuff that was hacked and dumped many years ago by Shaltai Boltai,’ referencing a purported hack of Concord’s computer systems that occurred in approximately 2014.”

Prosecutors add that the defense’s “hypothesis is not consistent” with the presence of “actual discovery materials” on the website.

The special counsel also describes technical details that were scraped from the publicized discovery. The names and numbering of the documents in question “significantly match the non-public names and file structure” of the discovery materials, prosecutors write. Also, a database program called “Relativity” was purportedly used to sort and store the filings, for example, suggesting “that the data was not taken from the Special Counsel’s Office or the U.S. Attorney’s Office, because the government has not used Relativity databases to store data related to this case.”

The Mueller filing comes amid an ongoing discovery dispute in the case.

Concord has objected to the limitations placed on its American legal team regarding the sharing of discovery in the case. Mueller had sought to block discovery being shared to those outside the legal team — and particularly Yevgeny Prigozhin, the Kremlin-aligned executive of the company who was also charged by Mueller but has not submitted to the court’s jurisdiction — for national security reasons.

Late last year, the company requested that the judge loosen those restrictions in a series of filings alleging that prosecutors were being too aggressive in deeming certain discovery materials — including spam emails and naked selfies — sensitive for national security reasons. Concord’s lawyers argued that sharing those materials with Prigozhin — known in Russia as “Putin’s Chief” for the facilities services he provides to the Kremlin — and others outside the legal team is necessary for their defense in the case.

In Wednesday’s filings, Mueller called out Prigozhin in the most explicit terms yet for trying to have his cake and eat it too by hiring lawyers to defend his company in court, while refusing to appear in the U.S. to fight the charges.

That he is not being allowed access to discovery is “a problem of Concord’s own making,” Mueller says.

“After all, it was (apparently) Prigozhin’s choice to have Concord enter an appearance in this criminal case, knowing that he was under indictment but declining to appear himself, let alone accept notice of the indictment,” the filing says.

Mueller wrote elsewhere in the document that allowing the discovery to make its way to Russia could pose a threat to national security.

“Unwarranted disclosure of that information overseas, in a country adverse to this litigation, would allow that country and actors in that country to learn of these techniques and adjust their conduct, thus undermining U.S. national security interests, including investigations into the conduct of those foreign actors,” prosecutors write.

Read the filing below: