I realize the police have to do their job somehow. But if the subject was a white male, 160 lbs, with a winter hat on and I happened to be near the scene of the crime, I can't imagine the police ever bringing me in for questioning even though I'd fit the description as well. They'd take one look at me, see I'm a nerdy white guy with a good-old American name, ask me if I'd seen anything, and then let me go.
There is a time and place factor here together with a description; they are not randomly stopping someone in a random location at a random time just for looking black.