Broadly speaking, you will only rarely find police properly prosecuted for their misdeeds. Usually, the worst that happens is dismissal, if even that. Of course there are outliers - cops who wrongly kill people have been prosecuted from time to time, but even then, their chances of escaping justice are higher than for an individual citizen in their place.

There are many reasons for this, but in my humble opinion, the worst one is the "thin blue line" - the idea that police are a brotherhood holding back the darkness of crime and evil, which leads to the idea that their misdeeds are somehow excusable by people "on their team", which includes other cops and citizens who are aligned with them.

In my opinion, police should be held to a higher standard by society to match the higher level of trust, protection, and presumption of regularity that we give them. If they commit crimes, they should be prosecuted even more zealously and reliably than laypeople, rather than only rarely.

Prosecutors are insufficiently independent from cops. The job of prosecutor is often as political steppingstone. Prosecuting cops isn't compatible with that.