Memos are also expected to be released later this week regarding former Trump confidants Paul Manafort and Michael Cohen, both of whom have been found guilty of multiple federal crimes as a result of the Mueller probe.
Prosecutors on Tuesday filed a sentencing memorandum in the case of Flynn, who pleaded guilty past year to lying to the Federal Bureau of Investigation regarding conversations about sanctions with the Russian ambassador.
Trump also praised another former advisor, Roger Stone, for refusing to testify against him - drawing accusations of witness tampering and illegally obstructing the Russian Federation collusion investigation of Special Counsel Robert Mueller.
In September, the special counsel's office officially scheduled December 18 for Flynn's sentencing.
The filing by special counsel Robert Mueller provides the first details of Flynn's assistance in the Russian Federation investigation, including that he participated in 19 interviews with prosecutors.
Iowa Hawkeyes headed back to Tampa for Outback Bowl
The Buckeyes trounced Northwestern 45-24 on Saturday night, one week after routing archrival MI in their annual showdown. It missed out in the 2015 season and previous year , when Pac-12 teams combined to go 1-8 during bowl season.
Once one of the real estate tycoon's closest allies and a top executive at The Trump Organization, Cohen has become a key witness in Mueller's investigation into whether the Trump campaign colluded with Russians in 2016.
Cohen, once Trump's self-described "fixer", admitted he lied to Congress when he said efforts to pursue the Moscow project ended in January 2016, when they actually continued until June 2016, after Trump had clinched the Republican presidential nomination. CNN's Manu Raju observed that Trump is offering a "big signal here" that he could pardon Stone and is "encouraging him not to cooperate". He faces a maximum sentence of five years in prison based on the charges he pleaded guilty to.
He has instead spent considerable time with his family and worked to position himself for a post-conviction career.
Flynn also admitted to lying on his foreign lobbying registrations about his lobbying in Turkey. 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 USA elections.
"The defendant provided firsthand information about the content and context of interactions between the transition team and Russian government officials", it noted. According to the filing, Flynn has been cooperating in "several ongoing investigations". The sentencing is scheduled on December 12.
Department of Justice veterans told INSIDER that they had never heard of a cooperator maintaining contact with the potential target of an investigation after striking a deal with prosecutors and that such communications could tank a cooperation agreement.