Flynn is prepared to testify that Trump directed him to make contact with the Russians, in the context of plans to defeat ISIS.
The document that was filed with the indictment in a Washington D.C. court, lists statements from Flynn as to why he would have met with Russian officials and who may have directed him to do so during the transition between President Barack Obama's administration and the incoming Donald Trump administration.
The government did not reveal the identity of the senior transition official.
The probe focuses on Russian meddling, and potential plans between Russia and Trump's campaign aimed at sending the billionaire to the White House.
Given that Trump publicly thanked Russian President Vladimir Putin on December 30 for not retaliating, it has always been hard to believe that Trump wasn't aware of the Flynn-Kislyak discussions. His business dealings and foreign interactions have made him a central focus of Mueller's investigation.
The retired Lieutenant General retired from his post as national security adviser in February, after it came out that he had lied about his conversation with Kislyak.
President Trump's attorney Ty Cobb played down the importance of former National Security Advisor Michael Flynn's guilty plea Friday. The split from the White House suggested to many that Flynn was about to start coorperating with the independent investigation headed by Robert Mueller.
Early on in is administration, Trump had taken a particular interest in the status of the Flynn investigation. The White House has denied that assertion.
Court papers make clear that Flynn knows the identities of at least two members of Trump's transition team who were aware of his outreach to Russian government officials in the weeks before the inauguration. At a time when tensions were hightened between the U.S. and Russia, Flynn was asked about whether he discussed sanctions against the country with the ambassador before he took office. In charging Flynn, prosecutors made clear they believe that claim to be false.
Flynn didn't speak in court, other than to say he would plead guilty.
Signs of Flynn cooperating with Mueller's team surfaced in the past week, as his lawyers told the legal team they could no longer discuss information about the case with them.
Flynn is now accused of "willfully and knowingly" making "false, fictitious and fraudulent statements" to the feds.
In a striking rupture with past practice, the Obama administration refrained from vetoing the condemnation, opting instead to abstain.
The Obama administration abstained, while the rest of the 15-nation council, including Russian Federation, voted unanimously against Israel. On December 22, Trump spoke with Egyptian President Abdel Fattah al-Sisi before the scheduled vote.
The vote occurred a day later, with Trump tweeting after: "As to the United Nations, things will be different after January 20th".