St. Louis County's top prosecutor said on Thursday that charges would not be brought against the former police officer who shot and killed Michael Brown — a Black teenager — in August 2014.

The decision followed a lengthy review of the encounter that led to Brown's death.

“In the end, we cannot ethically bring this case to trial,” St. Louis Country Prosecutor Wesley Bell told the St. Louis Post-Dispatch, though he noted that his decision didn't exonerate Darren Wilson, the former officer responsible for Brown's death.

When Bell, the county's first Black prosecutor assumed office in January 2019, many civil rights activists were hopeful that he would re-examine the case. Last August, on the fifth anniversary of Brown's death, Brown's family made a public plea for the Bell to reopen the case.

Brown was shot dead by Wilson, who is white, on Aug. 9, 2014, in the St. Louis suburb of Ferguson. A grand jury decided a few months later not to charge Wilson.

The following year, the Justice Department said that Wilson's actions were justified and that he couldn't be charged federally. A further review of the Ferguson Police Department by Justice Department, however, found that the police force had an established track record of unfairly targeting the municipality's majority-minority population. 

The killing of Brown sparked national outrage and protests, and was one of the initial catalysts for the Black Lives Matter movement.

The movement has returned to national prominence in 2020 following the police killing of George Floyd, a Black man, in Minneapolis at the end of May.