Federal prosecutors say confidential material provided to a Russian company charged by special counsel Robert Mueller was altered and released "as part of a disinformation campaign" to discredit the American investigation.
Prosecutors say in a new court filing that representatives of Concord Management and Consulting LLC should not be permitted to view additional sensitive evidence outside of the United States because it risks national security.
They cite a Twitter account that surfaced in October 2016 purporting to have a stolen copy of evidence provided to the company. Some file folder names and folder structure on the webpage matched what the Mueller team had produced.
Concord is one of three entities and 13 individuals charged by Mueller in a conspiracy to spread disinformation on social media during the 2016 presidential campaign.