Flynn served as Trump's national security adviser for less than a month in early 2017, but was sacked more than two weeks after then-acting Attorney General Sally Yates told White House officials that Flynn had lied to Vice President Mike Pence about his communications on Russian sanctions with then-Russian ambassador to the US Sergey Kislyak.
Prosecutors said in a court filing that Flynn had provided "substantial assistance" in Mueller's probe, including giving "firsthand information about the content and context of interactions between the transition team and Russian government officials".
Robert Mueller said Cohen had cooperated
Cohen became a person of interest early on in the investigation, given his close connection to the president and business contacts in Russian Federation.
US President Donald Trump has called for a "full and complete" sentence for his former lawyer Michael Cohen, weighing in on a judicial proceeding with accusations Cohen lied about dealings with Russian Federation during his 2016 presidential campaign.
Flynn's false statements stemmed from a January 24, 2017, interview with the Federal Bureau of Investigation about his interactions with Sergey Kislyak, Russia's then-ambassador to the USA, as the Obama administration was levying sanctions on the Kremlin in response to election interference.
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. One knowledgeable source said Flynn's cooperation largely took place immediately following his December 2017 court appearance. Manafort, Trump's former campaign chairman, was found guilty on eight counts of financial crimes. Flynn was sacked from the White House on February 13, 2017, after he misled Trump administration officials, including Vice President Pence, on his communications.
Mr Flynn's short tenure as Mr Trump's national security adviser ended in February 2017 after just 23 days. He is now serving a 14-day prison sentence. Unclear. We do know that Mueller has referred information to the Southern District of NY, including the criminal investigation of Michael Cohen that led to his guilty plea for campaign finance violations, as well as bank and tax fraud.
In a series of tweets on Monday, Trump accused Cohen of co-operating with federal prosecutors in the Russian Federation probe in exchange for a reduced sentence on unrelated tax fraud and campaign finance charges.
But Trusty said that during the FBI's investigation of Hillary Clinton's private email server, investigators and Comey "swore off even pursuing false statements charges", quoting a recent Justice Department inspector general report. Trusty said. "It's a fair question that someone in the Federal Bureau of Investigation or Justice Department ought to answer at some point".