In a court filing on Wednesday, Mueller said that the US' national security interests would be jeopardised if Concord is allowed to share the sensitive evidence in the criminal case with Russian Federation.
"In the filing, Mueller's team said "non-sensitive" evidence that had been shared exclusively with Concord's USA law firm, Reed Smith, had wound up being disseminated, purportedly as a result of a hacking operation targeting the law firm", Bloomberg reported.
Yevgeny Prigozhin is Russian Oligarch with close ties to Russian leader Vladimir Putin.
Russian hackers stole and then misrepresented evidence connected to the continuing prosecution of Russian companies accused of leading a propaganda campaign to influence the 2016 U.S. election, a court has heard.
On February 16, the US Justice Department said that the United States had indicted 13 Russian nationals and three entities, including Concord Management, for allegedly trying to interfere in the 2016 US presidential election. Concord is the only defendant to respond to the allegations in court, which means its attorneys have access to evidence in the case.
They cited a Twitter account that surfaced in October 2016 purporting to have a stolen copy of evidence provided to the company.
The published links included 'file folders with names and folder structures that are unique to the names and structures of materials (including tracking numbers assigned by the Special Counsel's Office) produced by the government in discovery'. Trump has repeatedly slammed the Mueller investigation as a "witch hunt" and insisted there was "NO COLLUSION" with Russian Federation.More news: Ivan Perisic Submits Transfer Request At Inter Milan
The fake documents were sent to ThinkProgress reporter Casey Michel and independent disinformation researcher Josh Russell in November in direct messages from a Twitter account called @HackingRedstone.
An FBI analysis of the files found that only about 1,000 of the 300,000 released were real documents provided to Concord by Mueller's team.
Prosecutors say that whoever created the webpage had access to at least some of the material provided by Mueller in the case.
Prosecutors say they do not oppose allowing Concord's corporate officers to see the evidence.
Also Wednesday, Trump said he would let the Justice Department decide how to handle the special counsel's repor.
Matthew Whitaker, the acting attorney-general, said this week he had been fully briefed on Mr Mueller's inquiry, and that the final report was coming soon. Trump told the Daily Caller he has not spoken to Whitaker about whether the investigation is nearing its conclusion. The special counsel argued that sharing the information outside the US could expose American secrets to the Russian government - a concern shared by legal and national security experts.
Trump has also denied any connection between his campaign and Russian Federation, calling Mueller's probe a "witch-hunt" that has produced no evidence thus far.