Here's What We Know About Mike Flynn Cooperating With Mueller

The President's former national security advisor has been most helpful to Mueller in building a criminal case.

Michael Flynn, the President's former National Security Advisor, really, really cooperated with Robert Mueller's…

According to court documents filed by the Mueller investigators, Flynn admitted to lying about his conversations with Russia's ambassador prior to the inauguration and also lying to the FBI. Flynn also lied to the Vice President.