Funny. I never thought of death as an "injury."
IANAL, but my guess is that the DA is waiting on the coroner’s report to upgrade to some form of homicide. If they don’t do everything by the book a defense attorney might find some way to get them off, get the charges reduced, or be a better position when negotiating a plea-bargain. Again, IANAL, YMMV, BYOB, etc.
It’s because Obamacare is miraculous.