No word if the if the USA for the District of Nevada has opened up a criminal civil rights investigation, but if this transcript is accurate, they should.
Hell will have long been frozen over before they open an investigation of any kind. The cop was only putting the slave in his place. If he is not showed where his place is, he may start thinking he is as good as the cop. Hell, any of the Cops-Can-Do-Wrong crowd can tell you that that is not the case.
The police stopped being the law abiding citizen's friend long ago.