I see what you did there. But Jeremy knows, so does Julie Mugford - and, vicariously, so do we.
JB knows whether or not he was involved. If he was involved then obviously he knows exactly who was shot where and when. If he wasn't involved he will probably know less than we do here.
JM knows whether or not her testimony at trial was truthful. it wasn't truthful it could still mean JB was involved and he simply didn't tell her. If it was truthful JB may have said it as a wind-up.
A professional reconstruction will be unable to produce anything akin to cctv but what it will do is show NB's exact position in the farmhouse when he sustained the 4 upstairs gsw's along with the perp's location when he/she inflicted them and this is the most contentious part of the reconstruction:
- Did JB enter his parents bedroom, who up until that point were in bed, and open fire meaning NB was then unable to have made the call to JB as per the pathological evidence and lack of bloodstains on the phone or;
- Was NB already downstairs in the kitchen making the tel call to JB whilst SC went upstairs opened fire on June. NB hearing the shots and/or June left the phone call, run upstairs and as he was stood on the landing stairs immediately preceding the bedroom he sustained the 2 gsw's to his face which SC inflicted from just inside the bedroom. NB then turned to retreat downstairs with SC following and inflicting the two gsw's to his rear whilst the pair were positioned on the main staircase.
Unlike witnesses the physical evidence, of which there's a huge amount in this case, is capable of revealing the truth, which imo will show NB sustained all 4 gsw's as I've described above on the landing stairs and main staircase.