I think it is unwise to try and stop a crime not directed at your person if the perpetrator is black. You may save a life, but you go to jail and possibly cause another riot.
For your sake, I hope that it is never a member of your family that needs someone to come to their aid. Is this what we have come to as a society? Afraid to help one another for fear of reprisal. If so, we have lost our Country!