turns out to be likely related to poverty more than race. Not unexpected. The data apparently correlates with personal circumstances and economics. Presumably there is the odd bad apple in the police. But the issue of racial prejudice isn't obviously systemic. It's a poverty problem.
"This is not just about drugs or law enforcement. Poverty plays an essential role in all of this. Jens Ludwig, an economist at the University of Chicago who also directs the Crime Lab there, points out: “Living in a high-poverty neighborhood increases risk of violent-crime involvement, and in the most poor neighborhoods of the country, fully four out of five residents are black or Hispanic.”"
http://www.nytimes.com/2015/10/18/upshot/police-killings-of-blacks-what-the-data-says.html?smprod=nytcore-ipad&smid=nytcore-ipad-share