On Jan. 2, 2021, former President Donald Trump asked Georgia Secretary of State Brad Raffensperger to "find" the votes needed to win the state in the 2020 election.

The now-infamous phone call helped spark a criminal investigation launched the following month by Fulton County District Attorney Fani Willis looking into the efforts by Trump and his allies to overturn the results of the 2020 election.

For a timeline on how the probe has unfolded, click here.

-ABC News' Meredith Deliso and Olivia Rubin

Who are the key players in the criminal probe into former President Donald Trump's alleged election interference?

Some are local officials, including Georgia Secretary of State Brad Raffensperger, who certified the state's election results, and District Attorney Fani Willis, who is expected to bring the case before a grand jury as soon as Monday.

Others were working with Trump during or after the election, including his former lawyers Rudy Giuliani and John Eastman, both of whom appeared before a special grand jury.

And there were also 16 "fake electors" who allegedly participated in a scheme to overturn the state's election results were notified that they were considered targets in the criminal investigation, prosecutors in court documents last year.

-ABC News' Meredith Deliso

Many eyes are watching Fulton County District Attorney Fani Willis as her investigation into alleged efforts by former President Donald Trump and his allies to overturn his 2020 election loss in Georgia nears its end and a potential fourth indictment looms for Trump, who denies all wrongdoing.

A charging decision is imminent. Willis is expected to present her findings to a grand jury this week.

"I would hate to have Fani Willis after me," Judge Jerry Baxter told ABC News. "She is a superb trial lawyer and the real deal."

-ABC News' Alexandra Hutzler

The Fulton County district attorney who has been probing former President Donald Trump's alleged efforts to overturn the 2020 election results in Georgia is expected to begin presenting the case to a grand jury on Monday morning, sources familiar with the matter tell ABC News.

The presentation from the Fulton County District Attorney's office comes after a two-and-a-half-year probe into the matter.

A spokesperson for the DA declined to comment.

This grand jury that will hear the case is a typical grand jury that has been seated for weeks and has heard other cases unrelated to the Trump probe.

It is not immediately clear how long the presentation will take.

Trump has denied any wrongdoing.

-ABC News’ Olivia Rubin

Multiple witnesses have been spotted and testified before the Fulton County grand jury today, including two former state lawmakers.

Former Democratic state Sen. Jen Jordan testified today, she told local outlets as she left the courthouse, saying she testified for about 40 minutes.

Former Democratic state Rep. Bee Nguyen also testified, according to a statement.

"Today, I testified in front of the Fulton County Grand Jury," the statement said. "When I took my oath of office in 2017, I swore my allegiance to our Constitution and promised to protect and defend our State and our country. On December 2020, when Rudy Giuliani and the former President’s legal team appeared before the Georgia House of Representatives, I upheld my oath and told the truth in the face of false testimony about our elections."

"Today, I reaffirmed my allegiance to our State and country -- by exercising my patriotic duty as a U.S. citizen and telling the truth under oath," she continued. "As a former lawmaker, I respect the separation of power and the crucial role that our judicial system plays in protecting our democracy by holding everyone accountable, even powerful individuals."

Georgia election official Gabriel Sterling, who spoke exclusively with ABC News’ Jon Karl over the weekend, was also spotted in the courthouse by The Atlanta Journal-Constitution.

-ABC News' Olivia Rubin, Will Steakin, Laura Romero and Richard Elliott