Do an internet search, as there are multiple versions of this story floating around. The initial report was that the stepfather said that the officer came in and said "we don't have time for this.....taze him." and that the 18 year old started resisting at that point. The two officers that were "holding the boy down" have already been cleared and issued statements saying that have no doubt that upon a full review that the shooting will be justified.
Just be careful of how this is being spun. There are definitely at least two sides to this story.