A request for immunity isn’t an admission of guilt or wrongdoing. It may be sought by witnesses who fear that their words could be used against them, as a condition of their testimony. The Journal previously reported FBI agents had questioned Flynn in January shortly after the Trump administration denied he had spoken with Russian Ambassador Sergey Kislyak the previous month. While the precise nature of that interview is unknown, it is a federal crime to lie to the FBI during a criminal investigation.

But the move could also be a purely prophylactic measure. “Not withstanding his life of national service, the media are awash with unfounded accusations, outrageous claims of treason, and vicious innuendo directed against him,” Kelner said. “He is now the target of unsubstantiated public demands by Members of Congress and other political critics that he be criminally investigated. No reasonable person, who has the benefit of advice from counsel, would submit to questioning in such a highly politicized, witch hunt environment without assurances against unfair prosecution.”

Flynn’s prominent roles in the Trump campaign, the presidential transition, and the first month of the administration placed him at the center of the president’s inner circle during its most pivotal months. That preeminence came to an abrupt end last month when he was fired by President Trump last month for lying about his conversations with the Russian ambassador during the transition. The former Army general had previously been dismissed by the Obama administration after a rocky tenure as head of the Defense Intelligence Agency in 2014. In both positions, Flynn’s combative management style reportedly alienated top White House officials in the Obama and Trump White Houses.

The controversy that eventually led to Flynn’s ouster began in December, when the Obama administration imposed sanctions against the Russian government. The U.S. intelligence community accused Moscow of using cyberthefts targeting the Democratic National Committee and top Clinton campaign officials to influence the 2016 presidential election and undermine Democratic candidate Hillary Clinton’s bid for the White House.

The same day the sanctions were announced, Flynn spoke with Kislyak multiple times by phone. He and top Trump administration officials subsequently denied reports that the two men had spoken, only to subsequently oust him as national security advisor after multiple news outlets reported that U.S. intelligence agencies had picked up conversations between them during their routine surveillance of foreign diplomats. It’s not unusual for those suspected of lying to federal authorities to seek immunity before testifying further.

Russia isn’t the only country haunting Flynn. Earlier this month, he filed paperwork with the Justice Department to retroactively register under the Foreign Agent Registration Act as a lobbyist for the Turkish government. Such filings aren’t unusual in Washington, where foreign countries often hire lobbyist firms to represent their interests or burnish their image. But Turkey’s contract with Flynn’s firm was signed in August, three months before Trump selected him to be the national security adviser. The White House later admitted after Flynn’s filing that it had known he could be required to register as a foreign agent before the inauguration.