Gates pleaded guilty in February to reduced charges of lying to the Federal Bureau of Investigation and conspiring against the United States and agreed to cooperate with Mueller. Mueller is investigating whether Trump associates were involved in the Russian activities. As both sides did in November, Tuesday's filing proposed updating the court about whether to set a sentencing date for Gates in another 60 days, on March 15. The filing also states that in another Justice Department investigation, Manafort provided information that appears related to an event while he was with the campaign in August 2016. It, along with the Federal Security Service (FSB), is alleged to have been involved in the Kremlin's effort to interfere in the 2016 US presidential election.
Manafort and Gates were indicted on financial crimes in October 2017 in Washington and for further offences in Virginia in February 2018.
An affidavit filed on Tuesday gives an in-depth look at special counsel Robert Mueller's investigation into Russian election interference, and revealed that Konstantin Kilimnik, a suspected member of Russian intelligence, was a central figure in the investigation.
Gates' plea agreement has precipitated almost a year of cooperation in the special counsel's probe.
"The government seeks to seal Attachment A (including its exhibits) and make the redactions reflected in Attachment B and its exhibits because the redactions relate to ongoing law enforcement investigations or uncharged individuals", Mueller said in a filing dated January 15.
The mistaken disclosure - caused by a formatting error that allowed redacted material to be viewed - triggered new concerns among legal experts and Democratic lawmakers about the extent of Manafort's Russian Federation ties during his time on Trump's campaign, which included three months as chairman.
Ahead of a second trial in Washington in September, Manafort struck a plea agreement of his own.
On 28 May 2018, according to Tuesday's filing, Manafort was sent a text message by an associate, who asked: "If I see POTUS one on one next week am I ok to remind him of our relationship?" Manafort replied: "Yes...even if not one on one".
The filing from last week also included a description of a meeting in which Manafort and his business partner, Konstantin Kilimnik, discussed a "peace plan" for Ukraine - understood to involve potential sanctions relief for Russian Federation - and a conversation in which Manafort authorized someone to drop his name if the person was able to secure a meeting with President Trump.
Manafort was then-candidate Donald Trump's campaign manager from March to August 2016.
Kilimnik himself has been charged by Mueller with conspiring with Manafort to try and tamper with witnesses in Manafort's criminal case. He also says his former lawyer, Cohen, lied to get a lighter sentence in NY.