Flynn’s son, Michael Flynn Jr., had been considered for a job in the Trump transition, but ultimately was rejected because of the controversy surrounding the messages he has pushed on social media. Among the false stories he promoted was a viral rumor dubbed “Pizzagate” that accused Democratic presidential candidate Hillary Clinton and her allies of running a child sex ring out of a pizza parlor in the District. A North Carolina man who believed the reports traveled to Washington last year with a gun, saying he hoped to help free the children. 

As Friday’s court filing makes clear, Flynn has been a major investigative target of the FBI’s probe into Russian meddling in the 2016 election. A key question for investigators is whether any Trump associates coordinated with Russian officials to try and sway the presidential race. 

Flynn’s contacts with Kislyak are a key issue in the probe, and the plea deal — which still has to be finalized before a judge Friday morning — could open new doors for investigators trying to determine what, if anything, President Trump knew about such contacts.

Flynn has also come under scrutiny for having a secret financial stake in major foreign policy decisions while advising Trump during the campaign, transition and in the brief period he served in the administration.