Possibly, DRH2 was the first shot fired to Sheila with the rifle held more upright by the killer, ejecting the spent casing to the right and further towards the head of Sheila, this was the none fatal shot, a more upright position of the rifle would send the casing in this position. Realising Sheila was still alive, the killer turns the rifle upside down and this allows him to lower the rifle more flat to the body, this then gives a more direct shot up through the scull and not angled, the casing then ejects to the left DRH1.
Having the sights removed from the rifle would allow the rifle to be in a lower position to the body and when turned upside down, his or her hands would be on top with the trigger guard?
DRH1 casing is more in line with a lower down rifle shot, DRH2 casing is further forward towards the head pointing to a higher rifle shot?
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