Right As Rain

Description for RIGHT AS RAIN by George P Pelecanos:

Derek Strange is black and successful. Terry Quinn is white and barely holding on. Now Strange has been hired to investigate a police shooting in which Quinn played a major role. For Strange, a savvy and careful man, the investigation goes against his style and instinct. For Terry Quinn, Strange's questions are a chance to absolve his conscience and shake out a little truth. But in a city that lives in the shadow of a nation's dream, neither man can foresee the dirty little war that will break out around them...or how deadly being right can be.

This is #2 in PI Derek Strange Series.