Its quite easy in some respects to try and make a scenario try and fit what happened except some illogical argument always crops up - for example I wondered if Sheila had some drug dealing friend in the house and a row had ensued and everything got out of hand and went horribly wrong - but then she would have fought to protect her children. Also I still can not believe 1) JB would have left the silencer ( if it had been involved) in a box in the house 2) and or told his girlfriend what he had done . However the one scenario that does fit totally is murder suicide by a poor girl that had not really been treated for her illness properly. Which strangely is what JB and the police believed in the beginning. The only problems with this scenario to me appear to be when people try and apply logic to her actions which because she was so ill can not be applied. I do believe JB is innocent .
Jeremy Bamber put his nail in his own coffin when he concocted the telephone call in the middle of the night from Nevill,who purportedly named Sheila as the person who had gained possession of one of his guns and was running amok. If you believe this story then you will deem Sheila as guilty in the legal sense but evidently not in a moral sense,as had she been apprehended after the slayings she would have ended up in Broadmoor for the rest of her days.
I'm afraid it's all too clear to me that the telephone call is a figment of Jeremy's imagination(some might say it was his worst mistake that morning among others)to grant himself an alibi with Police after cycling the short distance back to his Goldhanger cottage,which PC Wilkinson managed in six minutes on his run. The mystery in this case to my mind is not who the perpetrator is,but why Jeremy felt trapped in a situation whereby his only egress was through mass murder.There was no third person whom Jeremy could trust enough to execute the murders with him,though admittedly had Julie come down heavier on him during their hypothetical discussions he may have taken the hint and refrained from such a grisly course.
One is left with the conclusion that Jeremy had been harbouring a grudge for many years,that sense of thwarted ambition where Jeremy saw himself as leader of the pack instead of the hired hand,an experience which Nevill insisted he endure,though even here Jeremy was aware that there were trustees to convince before he gained the ultimate prize. As Jeremy moves the directional pad on his Gameboy,granting him the odd light relief in his prison cell he must regret the telephone call move,even if it seemed at that time a foolproof crime telephoning his answerphone,yet his gadgetry relieves the monotony of the protracted days as one merges into another amid those pervasive, frozen authority figures which to Jeremy's mind always were threatening, indecipherable and ultimately expendable.