The race of the cop in the foreground is completely irrelevant
Does the race of the cop matter if he's denying you your rights, and committing a false arrest? Does it make it any less police misconduct? I doubt very much that the victim would feel much better thinking, "Well at least the arrogant, dishonest, abusive cop arresting me is a brother!"
Absent further evidence, let's even set aside any possible racial profiling on the part of the arresting cop (the witness was certainly racially profiling but let's be generous and assume that the cop was not).
And Clarence Thomas is living proof that it's just as possible for a black judge to trample on our constitutional rights on a white judge.