That happens to me all the time.
As a black man I have more reason to fear a black cop than I would a white one. Many of the black cops have HNIC sickness, and the THINK they know how to profile other black men. They actually get a kick out of harrassing other blacks, pitting good blacks against the thuggish, and essentially taking their own self-hatred out on other blacks who appear to be higher on the social-economic scale, or would otherwise be intimidated by if they weren't employed as a cop. A lot of what's coming out about the personality of the Ohio cop, Bobby Cutts Jr., or that black cop in "Boyz in the Hood" is very typical of many of the cops I've had encounters with in DC.
If ever confronted by a white cop, I know if I behave and a not guilty of anything that I'll stand a good chance of getting by. A nasty, self-hating, narcisistic, piece-of-crap black cop will be quick to take notice of the way I talk, dress, and the Magen David around my neck, and will go on to make this moment in my life a living hell.
But then again, this is usually my experience with black cops in the more "whiter" sections of DC, which only reinforces my theory that these cops are full of self-hatred. Affirmative action cops indeed.