Uhmmm I think this article is a little incomplete. There are some pretty important information missing here, like:

1- What was the nationality of the driver/drivers?
2- Where they all the same nationality?
3- How old were they? It makes a huge difference how they get charged depending on whether they were minors or not.
4- How about the nationality of the person who died?
5- Also the deceased! It's unclear to me whether this was someone who was part of their street racing ring, or just an innocent bystander who had nothing to do with the whole thing?

Just some more clarification would be great. Also there's no such thing as Murder by Mistake. It's called Manslaughter or Murder 3rd degree.