Again, based on my experiences, you can be sure the doc and hospice covered their tracks very well. The medical examiner is probably the 'best that money can buy' as well.
You can bet that the fix was in before Micheal agreed to an atopsy.
As far as an atopsy being required by law, they haviolated so mny other laws in their quest to murder her that violating one more would have not mattered.