President Donald Trump’s former national security adviser Gen. Michael Flynn has been charged with making false statements to the FBI in special counsel Robert Mueller’s probe into Russia’s interference in the 2016 elections and the Trump campaign’s alleged collusion with the Kremlin.

Flynn is expected to plead guilty to the charge, perhaps as a part of a broader plea deal that could potentially result in more charges for Trump campaign or Trump administration officials. To date, Flynn is the closest figure to the president to have been charged with a federal crime, further raising the question of what did Trump know and when did he know it?

According to federal court documents, Flynn allegedly lied to the FBI while he was national security adviser. “On or about January 24, 2017, defendant Michael T. Flynn did willfully and knowingly make materially false, fictitious, and fraudulent statements and representations in a matter within the jurisdiction of the executive branch of the Government of the United States, to wit, the defendant false stated and represented to agents of the Federal Bureau of Investigation…”

Prior to Friday, reports had circulated indicating that Flynn’s defense attorneys were no longer in contact with Trump’s attorneys. The severed communications fueled speculation that more charges in Mueller’s wide-ranging probe could be on the way.

Flynn is the third person to be charged in the special counsel’s probe. Trump’s onetime campaign manager Paul Manafort was charged with multiple federal crimes to which he has pleaded not guilty. George Papadopoulos, a Trump campaign adviser, also pleaded guilty earlier this year to lying to the FBI.

Flynn is expected to plead guilty during a federal court appearance Friday at 10:30 a.m. ET.

This is a developing story. Check back for further developments.