In a surprise upset Tuesday night, a Ferguson, Missouri, councilman promising criminal justice reform ousted a 28-year incumbent St. Louis County prosecutor known nationally for his decision not to file charges against the police officer who shot Michael Brown in 2014.

Wesley Bell, a 43-year-old black man, campaigned on a variety of criminal justice reform promises, including one to rid the county of cash bail for nonviolent offenders, according to the St. Louis Post-Dispatch. When he won the Democratic nomination, he essentially guaranteed he will fill the St. Louis County prosecuting attorney position, as he is running unopposed in November.

But as much as Bell’s victory was a vote for reform, it was also a rejection of the system that allowed Darren Wilson, the officer who fired 12 bullets at teenager Michael Brown four years ago, to walk free. Incumbent prosecutor Robert McCulloch, a 67-year-old white man, was criticized by many after Brown’s killing when he chose to present the incident to a grand jury without a recommendation, rather than file charges against Wilson. The grand jury declined to indict Wilson.

McCulloch was widely expected to win re-election. But Bell’s supporters portrayed McCulloch as someone too harsh on offenders—especially nonviolent ones—and too easy on police.

According to the Post-Dispatch, after acknowledging defeat, McCulloch said that he would retire. He also said he had no regrets about how he handled the Michael Brown case.