According to a sentencing memo filed in court today, prosecutors say Flynn provided "substantial assistance" to investigators and "firsthand information about content and context of interactions between Trump transition team and Russian government officials".
Flynn's sentencing will take place on December 18, more than a year after he pleaded guilty.
The special counsel said that some of the information Flynn gave is sensitive, and related to ongoing investigations, so it asked that part of an addendum to the sentencing memo be sealed. However, his plea agreement states he is eligible for a sentence of zero to six months and can ask the court not to impose a fine.
In another tweet Monday, Trump praised another longtime associate, Roger Stone, who also has drawn Mueller's scrutiny, for having said he would never testify against Trump. In the same document, he goes further than in documents released last week by Special Counsel Robert S. Mueller III's office in which Cohen admitted to lying to Congress about his work on behalf of Trump when he was a candidate as he tried to secure approval for a hotel project in Moscow.
He pleaded guilty to lying to federal investigators on December 1, 2017, becoming the first high-ranking Trump adviser to agree to formally cooperate with the special counsel's probe.
Wall Street Cheers Ceasefire in U.S.-China Trade War
China imposed a retaliatory 25 percent tariff on imports of cars from the USA over the summer in response to Trump's own tariffs. However, Chinese attacks on USA companies ratcheted up again when the United States first implemented trade tariffs in July 2018.
"The defendant has also assisted with the SCO investigation concerning links or coordination between the Russian government and individuals associated with the Trump campaign", it read.
In this 2017 photo, National Security Adviser Michael Flynn speaks during the daily news briefing at the White House in Washington.
Flynn's case has been a contrast to those of other Trump associates, who have aggressively criticized and tried to undermine the Russian Federation probe. Also, Paul Manafort, a convicted felon who just blew up his cooperation deal with Mueller, is "a courageous man" who "refused to 'break'" and therefore has earned "such respect" from Trump.
When confronted by FBI agents about the conversations, court papers say Flynn made "material false statements and omissions", which impeded what was then an FBI counterintelligence investigation. It points to a conversation Flynn had with the Russian envoy, Sergey Kislyak, after then-President Obama had announced sanctions against Russia for its interference in the US elections.
Russian Federation denies election meddling and Trump describes the investigation as a political witch hunt.
He is at the center of what's believed to be an investigation into whether Trump obstructed justice.