"Violence was always just beneath the surface" - Colin Caffell.
He also does talk about actual physical violence among them.
Jeremy wanted to kill his family - Julie and various others testified to that!
The notion that Sheila was responsible is just as convoluted - Sheila in the throws of psychosis works out how to insert the magazine into a rifle she has never even prior. Works out how to chamber the first shot. Heads upstairs and shoots June while Nevill does nothing? He had to be in the bedroom to receive the initial shots so why didn't he mention he'd been shot to Jeremy? If he made the call to Jeremy first and then heard shots, saw June had been shot, why would he approach Sheila with a loaded gun and risk being shot himself? Surely he would try and lure her away from June and try and raise the alarm. How would the phone end up being off the hook if Sheila was upstairs shooting June when Nevill ended the call? It would take the same amount of time to replace the receiver as it would to place it on the bench and depress the button, in fact, probably less and it would be a natural reaction to replace it on the cradle. After being shot himself, he runs downstairs again - is he calling the police this time? Weird if he did because there's still nothing about him being shot on the (so called) rediscovered log? If things had escalated from a simple call to Jeremy asking him to come over, to then being forced by circumstances to call the police, why isn't any of that mentioned on the log? Both logs give the same information about sister/daughter going crazy/berserk with a gun. Nothing about anyone being shot!