CLAYTON, Mo. (AP) — St. Louis County’s prosecutor announced Thursday that he will not charge the former police officer who fatally shot Michael Brown in Ferguson, Missouri, a dramatic decision that could reopen old wounds amid a renewed and intense national conversation about racial injustice and the police treatment of people of color.

Prosecuting Attorney Wesley Bell’s decision marked the third time prosecutors investigated and opted not to charge Darren Wilson, the white officer who fatally shot Brown, a Black 18-year-old, on Aug. 9, 2014. A St. Louis County grand jury declined to indict Wilson in November 2014, and the U.S. Department of Justice also declined to charge him in March 2015.

Civil rights leaders and Brown’s parents had hoped that Bell, the county’s first Black prosecutor who took office in January 2019, would see things differently.

“My heart breaks” for Brown’s parents, a somber Bell said during a news conference. “I know this is not the result they were looking for and that their pain will continue forever.”

Describing the announcement as “one of the most difficult things I’ve had to do,” Bell said that his office conducted a five-month, unannounced, review of witness statements, forensic reports and other evidence.

“The question for this office was a simple one: Could we prove beyond a reasonable doubt that when Darren Wilson shot Micheal Brown he committed murder or manslaughter under Missouri law? After an independent and in-depth review of the evidence, we cannot prove that he did,” Bell said.

But, he said, “our investigation does not exonerate Darren Wilson.”

Wilson’s attorney, Jim Towey, said it was clear after three investigations that Wilson did nothing wrong.

“We all had the same conclusion: There was no crime,” Towey said.

“I am just hoping that everybody gets to have some closure, particularly the Brown family,” he said.

The shooting touched off months of unrest in Ferguson and made the St. Louis suburb synonymous with a national debate about police treatment of minority people. The Ferguson unrest helped solidify the national Black Lives Matter movement that began after Trayvon Martin, a Black 17-year-old, was shot to death by a neighborhood watch volunteer in Florida in 2012.

The issue has taken on new life since George Floyd’s death in Minneapolis in May after a white police officer pressed his knee into the handcuffed Black man’s neck for nearly eight minutes. Ferguson is among the cities around the world that has seen protests since Floyd’s death.

“This is a time for us to reflect on Michael’s life, to support Michael’s family and to honor a transformative movement that will forever be linked to his name,” Bell said.

Brittany Packnett Cunningham, a Ferguson protester and educator who has become a national voice in the Black Lives Matter movement, said she is pained “that there is still a gaping wound” for Brown’s family. She said she knows that the system must change.

“I’m not disappointed — I’m fed up and ever more committed, truth be told,” Cunningham said.

The Rev. Darryl Gray, a leading St. Louis activist, agreed that the system is at fault, not Bell’s investigation.

“What came out of this is a recognition that the system is set up to protect police officers. We now need to begin to address the legislation the police hide behind,” Gray said.

Scott Roberts, senior director of criminal justice campaigns at Color Of Change, a national racial justice organization, said in a statement that Bell’s announcement “perpetuates a criminal justice system that fails Black communities by allowing police to operate with impunity.”

Bell — who ran as a reform-minded prosecutor promising to eliminate cash bail for nonviolent offenders and to increase the use of programs that allow defendants to avoid jail time — faced no restrictions in re-examining Brown’s death. Wilson was never charged and tried, so double jeopardy was not an issue. There is no statute of limitations on filing murder charges.

As the news conference drew to a close, an activist who said he is a friend of Brown’s father erupted in anger.

“It’s over! One term!” Tory Russell, 36, of St. Louis, screamed at the prosecuting attorney. Police officers gently led him from the room.

Russell later told The Associated Press that he had just spoken with Michael Brown Sr. “He is hurting, and he’s not accepting of this.”

The shooting happened after Wilson told Brown and a friend to get out of the street as they walked down the middle of Canfield Drive. A scuffle between Wilson and Brown ensued, ending with the fatal shot. Wilson said Brown, who was not armed, came at him menacingly, forcing him to fire his gun in self-defense.

Brown’s body remained in the street for four hours, angering his family and nearby residents.

Bell’s predecessor, longtime prosecutor Bob McCulloch, was accused by critics of swaying the grand jury to its decision not to indict Wilson — an accusation he emphatically denied. Wilson resigned days after McCulloch’s Nov. 24, 2014, announcement that the grand jury would not indict the officer.

The Justice Department also declined to charge Wilson, but issued a scathing report citing racial bias in Ferguson’s police and courts. A consent agreement calls for sweeping reforms that are still being implemented.

Bell, a former Ferguson councilman, upset McCulloch, a staunch law-and-order prosecutor, in the 2018 Democratic primary and ran unopposed that November.

Bell, who, like McCulloch, is the son of a police officer, formed a special unit to look into officer-involved shootings like the one in Ferguson, as well as cases of potential wrongful convictions.

Brown’s mother, Lesley McSpadden, asked Republican Gov. Mike Parson to reopen the investigation of Wilson in 2018, but Parson’s office said it had no legal authority to appoint a special prosecutor.