I think it's a very reasonable assumption that IF JB did it, he'd have attempted to clean the silencer. Perhaps badly, hurriedly and in poor light (possibly), but I can't believe he'd make NO attempt at all.
Yes, and that's one of the sticking points for me re his guilt. After having gone to all that trouble to murder his entire family and cover his tracks, I would have thought he would make some attempt to clean the outside of the silencer, or take it away with him and risk someone asking where it was.
The cleaning I've put down to him not being 'perfect'.
As to taking the silencer, or leaving it - there are pros and cons for both choices. If he takes it and is caught with it - it's going to take some explaining. What if it's found n the hedges etc? What if it's discovered MISSING from the house? or ballistics deduce a silencer was used, but it's nowhere to be found? - it's murder for sure then.
So if it he leaves it at the house - what's the best plan? I'd have THOUGHT it best to leave by the side of sheila (to make it look like she used, it, then took it off to shoot herself). If he puts it in a drawer, then it just doesn't make a lot of sense since makes sheila look less likely to kill herself, and if the police DO discover a silencer was used, they'll look for it.
Of course he may just have been a wild 25 year old kid who thought out his plan fairly well, but not well enough, did the deed, put the silencer back in the box as though it had never been used. Tried to clean it up, thought he'd done a good job, and assumed nobody would look that closely anyway, since it was suicide.
He wasn't a professional assassin that's for sure. So I think we just have to be careful of thinking of him as a mastermind (IF he did it at all). If he did do it, I think he got very lucky with regard to much stuff, but then very unlucky too if the only real reason he got caught was because the family suspected him and his girlfriend spilled the beans.
As far as I know, there's no evidence that the silencer was ever used (other than the circumstantial evidence of blood on and inside it). It's not like the fatal bullet inside sheila was proven to have travelled through that silencer first and thus categorically prove it was murder.
