I plan to make a detailed post on why i think it was Ann Eaton, but it will take some time.
IIRC Ann Eaton and her husband sold guns at one point.
Peter Eaton was definitely a gun dealer, but I am not aware that Ann Eaton had any real experience with guns. It would require somebody to know how to dismantle and re-assemble a silencer, and also to appreciate the particular evidential significance of the silencer in the first place.
Peter Eaton could do it. I think Robert and David could.
It does occur to me that Peter and Ann may have collaborated, but a David/Robert collaboration makes more sense to me, simply because of the recorded blood group.
Although I don't believe it would have mattered whose blood was put in the silencer as long as it was human, I think Sheila's blood group was known to the relatives anyway, and Robert knew he was the same blood group. This was in the days before DNA was mainstream knowledge, and the implications of genetic testing would not have been appreciated by the relatives (or even the police and FSS).
Other facts favouring Robert/David are:
- Robert, in his own frank diurnal confessions, hated Jeremy.
- Robert spearheaded the pressure on the police.
- Robert is the one who reported the silencer to the police.
- Peter and Ann had custody of the silencer and handed it to the police, meaning that David and Robert were at one remove from the exhibit and would have felt less nervous about contaminating it.
- David, on his own evidence, was the first to examine the silencer.
- David states he tampered with the silencer by removing blood from it.
- Peter will have informed David about the significance of the silencer.
- Both Robert and David would know how to dismantle and re-assemble the silencer.
- Both Robert and David would have had an opportunity to contaminate the silencer without arousing the suspicions of Peter and Ann. They knew what to do and it would have taken minutes.
I don't believe a conspiracy of this kind would have involved more than two people.
