I've lived long enough to have seen this tragedy play out many times. Two factors seem to appear in every case I've seen: Prejudice and Fear. The first barely needs mentioning although it's not only related to blacks. Just about every immigrant group has been the target at one time or another.The second, fear, may require some explanation. Fear not only motivates the perpetrator, the bad cop, but also the victim. Cops fear when they feel out of control, generally because they lack adequate training. I saw this play out in Honolulu when I was stationed in Hawaii. The Honolulu PD had run up a startling record of incidents of excessive force until a new mayor invested in added training in both martial arts training and psychological methods of defusing potentially explosive situations. Shortly after the first cops graduated from the program there was an incident that demonstrated its effectiveness. Two cops had cornered a pair of perps in an alley. Before backup could arrive, one of the cops was wounded. His partner, without even drawing his weapon, talked the perps into surrendering. And yes, as I said, fear drives victims into responding defensively to encounters with law enforcement officers, and even minor encounters escalate into violence, especially when bystanders begin involving themselves on behalf of the persons officers are attempting to interview/arrest. Sadly, every time I've seen improved relations between the police and the community, someone stirs the pot. In some cases, the agitator is some well-meaning politician and in other times its a not so well-meaning politician. Sometimes the agitator is innocent of bad intentions and to often, they are intentionally stirring up trouble for personal gain. I don't expect to see an end of these incidents in the few years remaining to me, but I would love, at least, to see the hostilities cool back down again...