Investigation into Russian meddling in the 2016 election has found that Russian agents used social media to sow dischord and to distribute propaganda. It is also known that the president's son arranged a meeting with a high-powered Russian lawyer. But so far, exactly how far Robert Mueller's investigation about Trump's ties to Russia has gone remained a mystery.

Until now.

According to the New York Times, Trump's former national security adviser Michael T. Flynn pleaded guilty on Friday to lying to the FBI about having conversations with the Russian ambassador, Sergey I. Kislyak regarding the administration's foreign policy plans. This is a huge deal because Flynn is the first White House senior official to cooperate in connection with Mueller's election fraud investigation.

WATCH: Michael Flynn leaves court after he pleaded guilty to making false statements to the FBI https://t.co/Yh6lBZBWg7 pic.twitter.com/qO6bi0Yjj7— NBC News (@NBCNews) December 1, 2017

“I recognize that the actions I acknowledged in court today were wrong, and, through my faith in God, I am working to set things right,” said Flynn shortly after he submitted his guilty plea. “My guilty plea and agreement to cooperate with the special counsel’s office reflect a decision I made in the best interests of my family and of our country. I accept full responsibility for my actions.”

Flynn's plea agreement included documents confirming that he held foreign policy conversations that involved talk of getting rid of the U.S.' sanctions against Russia. Flynn also admitted that he received direction on how to discuss foreign policy from “very senior member” of Trump's presidential transition team, and that multiple members of the transition team knew that Flynn included talk of sanctions in his meetings.

In particular, court documents show that Flynn called Trump's Mar-a-Lago resort “to discuss what, if anything, to communicate to the Russian ambassador about the U.S. sanctions” with an unammed high-level official.

While the document doesn't name names, we do know that Vice President Mike Pence led the president's transition team, and top aides included Trump's son-in-law Jared Kushner, the first chief of staff Reince Priebus and K.T. McFarland, who now serves as the ambassador to Singapore. The documents didn't disclose what Trump knew about Flynn's discussions.

Trump and top aides did say earlier this year, however that they didn't know about Flynn speaking with the Russians, and that they definitely didn't know anything about him discussing sanctions.

Flynn resigned from his post with the Trump administration earlier this year; this resignation played a part in the firing of FBI director James Comey. After Flynn quit, Trump reportedly approached Comey and said to him, “I hope you can see your way clear to letting this go, to letting Flynn go."

For now, prosecutors plan to let Flynn go. Although he has pleaded guilty, prosecutors said that they plan to delay Flynn's sentencing, which some feel is evidence Mueller plans to use him to get more information about the Trump administration's dealings with Russia. Should he be convicted, Flynn faces a sentence of up to five years in prison.

The White House, for its part, was quick to distance itself from Flynn, a figure Trump once called “a very good person.”

”Nothing about the guilty plea or the charge implicates anyone other than Mr. Flynn,” said President Trump's lawyer Tyler Cobb.

Michael T. Flynn

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