Did that cop squeeze the life out of that guy with his knee? Yep
Will that cop ever be convicted and spend time in a prison cell. Nope
In cases like this, juries and courts overwhelmingly side with police officers...even against damning evidence. The FOP works closely with the courts, and our judicial system doesn't have the teeth to prosecute and convict bad officers. Good cops refuse to "cross the blue line" to testify against bad officers. If they do they are hated in their own departments. That kind of protecting "brother officers" makes them all look bad. The issue isn't police brutality the issue is police accountability.
Once I sat around a campfire with about a dozen cops. They went around the circle telling "cop stories" and one-upping each other. Most stories were about confiscating money, guns, & drugs that weren't on the books and never made it to the evidence room. Most of them don't give a fuck about civil rights even when cameras are rolling.
The illegal things you suspect they do, they do. And they get away with it.