AMinneapolis judge on Friday sentenced former police officer Derek Chauvin, for the murder of George Floyd last May, to 22.5 years in prison—a rare event in the nation’s criminal justice system, and one that many will regard as the end of a gruesome chapter in the American story.

“I begged for justice for my brother, some kind of accountability,” Philonise Floyd, George Floyd’s brother, said in a press conference after the sentence was passed.

Yet this moment also highlights a disturbing truth about policing and accountability, one that remains unresolved: prior to killing George Floyd, Derek Chauvin was one of a substantial number of officers who have been the subject of repeated civilian complaints but never faced serious discipline from their departments. The early warning signs of dangerous police conduct often go unheeded, police-reform advocates argue, and the officers involved are rarely punished and even more rarely face prison time. Even Minneapolis, the city perhaps most closely associated with public demands for policing reform, has, in the 13 months since Floyd’s killing, taken steps to curtail public knowledge of repeat officer misconduct. So, while Friday’s sentencing may represent a rare example of criminal penalties, the most severe form of officer discipline possible, it does little to address the existence of policing systems across the country that are not set up to head off problems before they get to that point.