http://www.theguardian.com/us-news/ng-interactive/2015/jun/01/the-counted-police-killings-us-databaseInteractive map from Guardian, more Whites are killed by Police Brutality than Blacks each year. However, since white population is far larger than black population, blacks killed represent greater percentage of the black population. Nevertheless, since blacks as a race have disproportionally higher crime rates than Whites, logic goes they will be in more negative interactions with the Police. Overall I think it evens out.
The issue is more about Police abusing his powers against an uncooperative suspect, little more. Though I would still give the Police, especially ones in America, the benefit of the doubt. When every suspicious criminal could be hiding a potential gun, I wouldn't take any risks myself.
The issue is a tragic one, but has definitely been politicized. A
certain party likes to take advantage of the tragedy to play race-baiting politics since it appeals so well to its voters.