By Sydney Kashiwagi, CNN

Alvin Bragg, a former New York state and federal prosecutor, drew national attention when he made history as the Manhattan District Attorney's Office first Black district attorney. Now, he is back in the spotlight after a grand jury voted to indict Donald Trump after a yearslong investigation into the former president's alleged role in a hush money scheme.

The indictment has been filed under seal and will be announced in the coming days. One source told CNN Thursday that the charges were not yet publicly known and Trump defense attorney Joe Tacopina said Trump will likely be arraigned in court early next week.

Bragg has remained tight-lipped on the details of the Trump probe, which he inherited from his predecessor, Cy Vance, who began the investigation when Trump was still in the White House.

Following news of his indictment, Trump claimed in a statement that it was "Political Persecution and Election Interference at the highest level in history."

Earlier in March, Trump announced on social media, ahead of any details from Bragg's office, that he anticipated he would be arrested within days in connection with the investigation. The Manhattan district attorney's office declined at the time to comment on the former president's remarks.

The high-profile case relates to a $130,000 payment made by Trump's former personal attorney Michael Cohen to adult film star Stormy Daniels days before the 2016 presidential election in exchange for her silence about an alleged affair with Trump a decade prior. Trump has continuously denied having an affair with Daniels.

The office's potential decision would mark the first time a former US president and major presidential candidate has been indicted.

In the lead-up to Bragg's decision, sources told CNN that city, state and federal law enforcement agencies in New York City had been discussing how to prepare for a possible Trump indictment, with the former president having called on his supporters to protest if he were to be arrested.

Discussions between the New York Police Department and the FBI also have focused on the possibility of increased threats against Bragg and his staff from Trump's supporters in wake of an indictment, sources told CNN. Bragg said in an email to staff earlier in March that his office will "not tolerate attempts to intimidate our office or threaten the rule of law in New York."

Trump among previous cases

Bragg has aggressively pursued Trump and other progressive priorities so far in his tenure, including not prosecuting some low-level crimes and finding alternatives to incarceration.

Before Bragg's swearing-in last year, he had already worked on cases related to Trump and other notable names in his role as a New York state chief deputy attorney general.

He said he had helped sue the Trump administration more than 100 times, as well as led a team that sued the Donald J. Trump Foundation, which resulted in the former president paying $2 million to a number of charities and the foundation's dissolution.

Bragg also led the suit against disgraced film producer Harvey Weinstein and his company, which alleged a hostile work environment.

The Harvard-educated attorney previously served as an assistant US attorney in the Southern District of New York, worked as a civil rights lawyer and as a professor and co-director of the New York Law School Racial Justice Project, where he represented family members of Eric Garner, who died in 2014 after being placed in an unauthorized chokehold by a then-police officer, in a lawsuit against the City of New York seeking information.

A historic election

Bragg emerged the winner in a crowded Democratic primary in the summer of 2021 to lead the coveted Manhattan District Attorney's Office, for which Vance had announced earlier that year he would not seek reelection. While campaigning, he often spoke about his experience growing up in Harlem, saying he was once a 15-year-old stopped "numerous times at gunpoint by police."

"In addition to being the first Black district attorney, I think I'll probably be the first district attorney who's had police point a gun at him," he said during a victory speech, following his historic election to the office. "I think I'll be the first district attorney who's had a homicide victim on his doorstop. I think I'll be the first district attorney in Manhattan who's had a semi-automatic weapon pointed at him. I think I'll be the first district attorney in Manhattan who's had a loved one reenter from incarceration and stay with him. And I'm going to govern from that perspective."

Bragg ran as a reformer, releasing a memo just days after taking office detailing new charging, bail, plea and sentencing policies -- a plan that drew criticism from police union leaders. He said his office would not prosecute marijuana misdemeanors, fare evading and prostitution, among other crimes.

This story has been updated with additional developments.

™ & © 2023 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.

CNN's Devan Cole, Kara Scannell and Sonia Moghe contributed to this report.