If a black man gets killed by a white man, and there is no video, and the black man is not famous or very very wealthy, the white man will get off. 99% of the time. It doesn't matter who started the altercation, or how, all it takes is the white guy, or is in this case the racist white guys, to claim self-defense, and they will not be charged.
As we saw in this case, there were no charges until a video got leaked. The simple fact is in America. Racist whites can murder blacks and get away with it if it's not caught on video.