Michael Flynn, President Trump's former national security adviser, was charged by Special Counsel Robert Mueller with one count of making false statements to the FBI.
According to court documents, Flynn was charged with one count of "willfully and knowingly" making false statements to the FBI. He pleaded guilty to lying to the FBI about his talks with a Russian ambassador.
Flynn’s lawyers had said they would no longer communicate with the White House legal team – a move that could signal his cooperation with the special counsel’s investigation or negotiate a deal for himself.
The judge overseeing Flynn’s case recused himself without providing a reason for doing so. Flynn’s sentencing is expected for February 2018.
Here’s a look at how Flynn – who was one of the more polarizing characters in Trump’s administration – is involved in the Russian investigation.
Why did Flynn leave the White House?
Flynn resigned as Trump’s national security adviser in February over revelations that he misled Vice President Mike Pence about his communications with Russia’s ambassador to the U.S., Sergey Kislyak.
How is he connected to the Russia investigation?
Despite earlier statements to the contrary, Flynn discussed sanctions former President Barack Obama imposed on Russia with Kislyak, Sally Yates, then the deputy attorney general, said in January. She said that put Flynn in a compromising position.
Flynn remains under multiple investigations by congressional committees and the Pentagon’s inspector general. He’s included in Mueller’s probe, as well.
Mueller’s investigation includes looking into whether Flynn attempted to obtain former Secretary of State Hillary Clinton’s deleted emails.
What do we know about Flynn's businesses?
Aside from Russia, Mueller has also been investigating Flynn’s lobbying work – particularly for a Turkish businessman.
Flynn Intel Group, Inc., carried out $530,000 worth of lobbying and research work for several months, including during the end of the 2016 campaign.
The lobbying campaign sought to gather derogatory information on Fethullah Gulen, a Turkish cleric and green-card holder living in Pennsylvania. Turkish President Recep Tayyip Erdogan has accused Gulen of being behind a botched coup and has sought his extradition. Gulen has denied the allegations, and U.S. officials have rebuffed Turkey's extradition demands, citing a lack of evidence.
Mueller is also investigating a meeting where Flynn allegedly discussed a plan that would pay him and his son up to $15 million to kidnap the U.S.-based cleric for the Turkish government.
Flynn filed as a foreign agent with the Department of Justice in March and acknowledged that the work he did could have benefited the Turkish government.
The Associated Press contributed to this report.
Kaitlyn Schallhorn is a Reporter for Fox News. Follow her on Twitter @K_Schallhorn.