In a federal probe originally meant to uncover Russian meddling in the 2016 election, Michael Flynn, former Trump National Security Adviser, has plead guilty to lying to the FBI. Specifically, he confessed to being dishonest over his talks with Russian Ambassador, Sergey Kislyak. The probe has expanded to investigate all possible ties between Trump’s administration and Russia.

According to New York Times, “Mr. Flynn’s plea agreement requires his full cooperation. He agreed to take a polygraph and, if asked, to participate in covert law enforcement activities. Such undercover activities are unlikely, however, since the plea agreement was filed publicly.” Flynn is the first official in Trump’s administration to cut a cooperation deal with the inquiry into Russian tampering in the election.

These new revelations about what exactly Flynn lied about have put the Trump Administration under closer scrutiny, especially Trump’s son-in-law Jared Kushner. It is still unclear what Trump knew about Flynn’s discussions. According to the New York Times, Trump’s lawyers believe that Jared Kushner was the one who ordered Flynn to have talks with the Russian Ambassador. The Times also reported, “documents say multiple members of the team coordinated the specifics of Mr. Flynn’s outreach to Russia and knew that the conversations were about sanctions.”

According to the New York Times, Flynn has plead guilty to lying “that he had not asked Kislyak on Dec. 29 ‘to refrain from escalating the situation in response to sanctions that the U.S. had imposed against Russia,’ and that he didn’t recall Kislyak telling him Russia had decided to moderate its response as a result of his request… Court documents also say Flynn falsely claimed that he didn’t ask Kislyak on Dec. 22 to ‘delay a vote on or defeat’ a U.N. Security Council resolution, and then falsely denied that Kislyak had described Russia’s response to the request. ”

The investigation was originally lead by James Comey, former FBI director, before he was fired by Trump in May. Robert Mueller is currently conducting the investigation, and this recent guilty plea marks a new phase in his investigation. The confession has the potential to shed new light on Trump’s tremulous  first few weeks in office, and will provide information from an insider in the Oval Office. According to NBC, officials in the White House are concerned that since Flynn advised the President on a number of sensitive matters, Flynn might say something damaging towards Trump.

Trump has refused to give a definitive answer regarding if he will stand by his former security adviser or what he thinks Flynn might tell the Russian probe. Though the penalty for lying to the FBI is five years in prison, federal prosecutors say Flynn will not serve a day in jail.