As with many other subjects, it turns out Richard Pryor was willing to talk openly about police brutality long before most other Americans. Here's a clip from his 1977 standup movie Richard Pryor Live in Concert (the whole thing is a masterpiece, by the way), wherein he almost perfectly describes future events, starting at the :38 mark. Here's the text, if you're too lazy to watch:

Police got a chokehold they use out here though, man. They choke niggers to death! That mean you be dead when they're through. Did you know that? Niggers go, "Yeah, we know!" Whites go, "No! I had no idea!" Two grab your legs, one grabs your head and go SNAP! "Oh shit, he broke. Can you break a nigger? Is it okay? Let's check the manual. Yep, page 8: You can break a nigger. Right there, see?"

Again, I urge you to listen to the full album if you've never heard it before, because onstage, Richard Pryor had a knack for being right about everything. And read Gilbert King's Devil in the Grove if you believe police brutality to be a figment of the imagination.