I suspect the increase in cases of police malfeasance/misconduct is (at least partly) tied to the 'militarization' of police departments. The following link seems to think so, too.

https://www.aclu.org/feature/war-comes-home

And of course you're right that cops are human and there are one helluva lot of good cops out there. But police brutality seems to be happening and whether we see more because it's exposed more is a question that needs answering. I'll see if I can find statistical support for that contention and get back to you. But what isn't questionable is the fact that police brutality is happening.