Michael Flynn, President Donald Trump’s former National Security Advisor, has offered to cooperate with the investigation into Russian interference in the 2016 election, The Wall Street Journal revealed Thursday. Crucially, Flynn’s offer — to the FBI and the House and Senate intelligence committees — reportedly comes with a demand for immunity, suggesting the information he has may concern criminal activity.

Here's what you need to know.

In a statement, Flynn's counsel, Robert Kelner, said his client "has a story to tell, and he very much wants to tell it, should the circumstances permit." Kelner denied any wrongdoing, saying the media is "awash with unfounded allegations" and "outrageous claims of treason."

While his lawyer protests his innocence, Flynn last year said immunity deals were a sign of guilt.

In a Sept. 25, 2016, appearance on NBC's "Meet The Press," he said of the FBI investigation into former Secretary of State Hillary Clinton's use of a private email server that, if "you are given immunity, that means you're probably committed a crime."

That quote cuts two ways, of course: The FBI, despite granting immunity to several Clinton campaign officials, dropped its investigation without charging anyone.

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Flynn resigned Feb. 13 after it was revealed he spoke to Sergey Kislyak, Russia’s ambassador to the United States, in December 2016 about potentially lifting sanctions targeting the Russian government.

Flynn had initially denied having that conversation. Then, after it was revealed that the conversation had been picked up and transcribed by U.S. intelligence officials, who had been monitoring Kislyak, Flynn claimed he couldn’t remember for sure what he discussed with Kislyak. That denial, in the view of the Department of Justice, meant “Flynn could be vulnerable to blackmail by Moscow,” The New York Times reported.

Flynn had also been interviewed by the FBI about the call, opening him up to potential perjury charges if he were found to have lied to the bureau.

An FBI spokesperson did not immediately respond to ATTN:'s request for comment.

USA Today reports that neither the Republican chairman of the House Intelligence Community nor the ranking Democrat have discussed granting Flynn immunity.

FBI Director James Comey confirmed in March 20 congressional testimony that there is an ongoing investigation into whether the Trump campaign coordinated with Russian officials to release hacked emails from the Democratic National Committee. The FBI and all 16 U.S. intelligence agencies have said Russian intelligence agents, acting on the orders of President Vladimir Putin, were behind the hacking and engaged in other active measures to hurt the campaign of Trump’s Democratic rival, former Secretary of State Hillary Clinton.

If he should testify before Congress or the FBI, Flynn is certain to be asked about his own ties to the Russian government. In 2015, for example, Flynn was paid $45,000 to attend a party in Moscow celebrating the 10th anniversary of Russia Today, a state broadcaster. Flynn also received a total of $22,500 from a Russian air cargo company and a cybersecurity firm, the Wall Street Journal reported.

If Flynn is actually granted immunity, however, that probably means investigators would be more interested in what, if anything, he could reveal about other Trump officials.

There's much to discuss. Paul Manafort, who chaired the Trump campaign before resigning in August 2016, was recently shown by the Associated Press to have been paid at least $10 million in 2005 to aid, “both internally and externally, the policies of the Putin government.” According to NBC News, Manfort also received "millions of dollars from a billionaire Putin ally" through at least one of 15 bank accounts and 10 companies he registered in Cyprus.

One Trump advisor says he communicated directly with Russian intelligence agents, while a Trump cabinet official falsely denied meeting with Russian officials head of the election.

Roger Stone, a former advisor to the Trump campaign, has also admitted to communicating with “Guccifer 2.0” — ostensibly a “hacktivist” behind the theft of DNC emails but, according to U.S. intelligence officials and private security firms, actually a front for Russian intelligence. As CNN notes, Stone also repeatedly “claimed knowledge of forthcoming leaks” and said he had a “backchannel” to Julian Assange, founder of Wikileaks, which posted the emails.

Attorney General Jeff Sessions, a Trump surrogate during the campaign, also met with Kislyak in a private meeting ahead of the election — contact he denied during Senate confirmation hearings. Sessions has since recused himself from the investigation into Russian meddling.

Flynn could also talk about his former boss.

President Trump himself has oft-expressed fondness for Putin's leadership style, and argued for more tightly cooperating with the Russia in the "war on terror" in Syria. USA Today also recently highlighted his business ties to Russian oligarchs and mobsters. However, there is no evidence he was in contact with any Russian officials, nor that he ordered his aides to cooperate with them on a campaign to hurt his opponent — indeed, there's no hard evidence that there was any such cooperation, though key claims in a dossier alleging as much, from former British spy Christopher Steele, continue to be verified as true.

The investigation into possible cooperation between Russia and the Trump team is also still in its early stages; when it comes to counter-intelligence probes, the FBI can spend years on a case without charging anyone with a crime. But things can move fast if officials implicated in such investigations start turning on each other.

While he's defiant, Flynn's testimony-for-immunity offer brings to mind the scandal that brought down former President Richard Nixon — and what triggered him to resign.

In June 1973, White House Counsel John Dean, in exchange for immunity, became “the first White House official to accuse the president of direct involvement in the Watergate cover-up,” The Washington Post notes. Watergate was the hotel where the Democratic National Committee was based, and where Nixon campaign officials ordered a break-in to uncover potentially damning information.

Nixon won the 1972 presidential election in a landslide but resigned in August 1972, just over a year after Dean’s testimony before Senate investigators.

The White House did not immediately respond to ATTN:'s request for comment.