Michael Flynn, Donald Trump’s onetime national security advisor, is slated to testify Thursday before the Fulton County special grand jury probing whether the former president or his allies criminally interfered in Georgia’s 2020 elections.

Flynn is one of the last remaining witnesses expected to appear before the 23-person grand jury, which meets in private and began hearing testimony in June. When the jury’s work is complete, it will author a report recommending whether Fulton’s District Attorney Fani Willis should press charges against any of the people who sought to undo Democrat Joe Biden’s narrow win here two years ago.

Flynn’s appearance is a victory for Willis, who has been fighting for his testimony for two months. He was compelled to appear after an appeals court in his home state of Florida denied his push for a stay on Tuesday.

Flynn’s attorneys did not respond to requests for comment, and a spokesman for the DA’s office declined to comment.

A former U.S. Army lieutenant general and director of the Defense Intelligence Agency, Flynn served for three weeks as National Security Advisor under Trump in early 2017. He stepped down after revelations that he misled Vice President Mike Pence about the nature of his communications with Sergey Kislyak, then Russia’s ambassador to the U.S.

Later that year, Flynn pleaded guilty to making false statements to the FBI during Special Counsel Robert Mueller’s investigation into Russian interference in the 2016 election. Trump granted Flynn a full pardon weeks after the 2020 elections.

Prosecutors previously indicated they’re interested in questioning Flynn about several issues:

  • The circumstances related to his pardon on Nov. 25, 2020
  • Comments he made during a Dec. 17, 2020, appearance on Newsmax, during which he said Trump could use the military to seize voting machines and “basically re-run an election” in swing states
  • A meeting he attended at the White House on Dec. 18, 2020, with Trump, attorney Sidney Powell and other Trump campaign officials, during which the group reportedly discussed invoking martial law, seizing voting machines and appointing Powell as a special counsel to investigate the 2020 elections
  • A draft executive order dated Dec. 16, 2020, that would have directed the secretary of defense to seize and analyze certain voting machines used in the 2020 election. It also would have appointed a special counsel to oversee the mission and “institute all criminal and civil proceedings as appropriate.” The order was never released but subsequently obtained by the Jan. 6 committee on Capitol Hill
  • A meeting Flynn reportedly attended at libel attorney Lin Wood’s South Carolina plantation following the November 2020 elections with Powell, former Overstock.com CEO Patrick Byrne and others allied with the Trump campaign “for the purpose of exploring options to influence the results of the November 2020 elections in Georgia and elsewhere,” according to his summons

Flynn, prosecutors previously said, “possesses unique knowledge concerning communications between himself and other known and unknown individuals involved in the multi-state, coordinated efforts to influence the results of the November 2020 election in Georgia and elsewhere.” They said his testimony was also likely to reveal additional sources of information.

Flynn’s lawyers previously argued the reasoning behind their client’s summons was based on “innuendo, speculation and supposition.” Seizing voting machines and invoking martial law, attorney Jason Greaves said last month, is “utterly irrelevant” because it never happened.

Since resigning his Trump administration post, Flynn has become a prominent figure among conspiracy theorist, far-right and Christian nationalist groups. He’s spent the last two years crisscrossing the country promoting his group ReAwaken America, which the Associated Press has described as a “recruiting tool for an ascendant Christian nationalist movement that’s wrapped itself in God, patriotism and politics and has grown in power and influence inside the Republican Party.”

In recent weeks, Willis has won a string of court fights filed by witnesses resisting their summons to come testify, including U.S. Sen. Lindsey Graham and former White House Chief of Staff Mark Meadows. Former House Speaker Newt Gingrich is still challenging his.

Fulton prosecutors have indicated the grand jury’s work is likely to wrap up in the weeks ahead. Once it issues its report, known as a special presentment, Willis must decide whether to accept or reject its recommendations. It’s still unclear whether the contents of the report – or any witness testimony – will ultimately be released to the public.