Many observers believe that if there was collusion between Russia and the Trump campaign, Manafort knew about it.
Judge Amy Berman Jackson said in court Friday that Paul Manfort, President Donald Trump's former campaign chairman, will participate in further interviews, hand over any requested documents, and potentially testify in future cases with special counsel Robert Mueller, according to the Washington Post . Manafort pleaded guilty Friday to two federal charges brought against him by Mueller as a part of the Russia investigation. The charges brought against him relate to tax evasion and his work as an agent for foreign governments -- as well as witness tampering. The plea follows a trial last month which found Manafort guilty on eight counts of bank and tax fraud.