If there were no grounds for stopping Bianca Williams then the Police have a case to answer. From what I've read Bianca Williams and her partner didn't behave that well but I must admit I feel uncomfortable about the use of handcuffs but I guess this is standard practice for all races which the Commissioner herself admits is in need of review. Let's wait to see what the Watchdog has to say particular to this case before assuming the Police are racists.
It was my understanding the Police Watchdog (Independent Office for Police Conduct) is independent of the Police and government.