There's no evidence of NB's blood in the main bedroom or casings his side of the bedroom other than the two attributable to SC. Dr Vanezis states the trajectory of the two facial shots were both 20 degrees below the horizontal. NB was taller than JB and SC.
The trajectory of the shoulder and elbow shots were also both downwards.
My theory is that the perp was in the main bedroom shooting June. As NB approached the main bedroom he was shot twice on the stairs immediately preceding the entrance to the bedroom in the lip and jaw. Casings 3 and 4 pertain to these shots. The perp was stood at the entrance with the barrel extending onto the landing but the ejection port just inside the door. NB then turned and fled down the stairs with the perp behind him. The perp then shot NB in the shoulder and elbow on the main staircase. Casings 13 and 14 pertain to these shots. The perp was parallel with the main bedroom door and the ejection port ejected cartridge 13 onto the transition plate of the main bedroom door. The ejection port ejected cartridge 14 to a similar location but it rolled down the stairs and landed a little way down the landing.
Two diagrams which may, or may not, support your understanding
Other docs and SoC photos supporting the above will be posted shortly.
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