It is possible to try to hold bad cops accountable and to bring charges against them when they are accused of misconduct, even in places with expansive union and civil service protections. But this requires so-called "good cops" to blow the whistle on the bad apples instead of simply complaining about being painted as guilty by association.

That's what happened in Rocklin, California, over the weekend. Officers who saw a fellow cop acting inappropriately reached out to their superiors; rather than trying to downplay what the officers said they saw, the higher-ups took the complaint seriously. The police chief reviewed body and dash cam footage and, agreeing with the cops who came to him, kicked the videos over to the district attorney for investigation.

Officer Brad Alford of Rocklin was arrested this week and charged with assault with a deadly weapon causing great bodily harm, assault under the color of authority, and filing a false police report.

The officers who blew the whistle on him were not identified, but along with Alford they were involved in the arrest of a man, also unidentified, suspected of driving under the influence. According to the police chief, Chad Butler, the officers informed their superiors that Alford "used a baton in a manner that appeared to be excessive."

After the chief requested the district attorney's office investigate the matter, the DA announced it had decided Alford's actions caught on tape "rose to a criminal level." Though the DA has already pressed charges, Butler insists the investigation is continuing, arguing this is was why he could not release video of the incident. The DUI suspect was taken to a hospital to be treated for injuries, according to a police spokesperson, but the department would not provide details on the nature of the injuries, citing privacy laws.

A lot could still go wrong. Because of California's civil service protections, the department cannot fire the officer immediately. And despite apparent video evidence, a conviction is not guaranteed. It requires guilt to be established beyond a reasonable doubt. That standard certainly should not be lower simply because the defendant is a cop. But the standard required for the government to deprive someone of his liberty need not be required for the government to deprive its own employees of a job.

A policy that aims to rid a department of bad cops before those cops become deadly could go a long way in improving policing. It could reduce police violence while also reducing the likelihood that police misconduct will compromise criminal investigations, as happened recently in Baltimore.