Manslaughter? It should be Murder 2 if you ask me.
You have to prove intent for a murder charge. If you watch the video there is no way they could prove it IMO. If this was not an L.E. officer it would probably be an ADW but they are going to make an example of him.
I do think it is interesting that the mainstream media is downplaying this though because of the ethnicity of the officer. If it was the other way around Sharpton and Jackson would be marching in the streets. My.02