It needn't be a murder charge. Manslaughter covers cases of negligence and someone, somewhere in the chain of the command must have been negligent IMO.

Add to that the fact that this guy was shot several times in the head AFTER he had been pinned to the floor (according to eye witness accounts) and that the initial investigations uncovered strong evidence of cover up and something stinks to high heaven. To proceed under 'health and safety' laws is franky farcical.