It would be very scarey if the silencer thing was a total load of rubbish, and unimportant from the start, and planted by a spiteful family member. Sheila (imo) wouldn't have bothered with a silencer. She would have just grabbed whatever gun came her way, and hope that it was loaded, and efficient enough to a) cleanly kill the boys b) kill June before June could stop her (she nearly made a mess of that) c) kill Ralph (another horrible mess) and d) kill herself before anyone could stop her. She must have known that Ralph was downstairs, calling the police, an ambulance, or JB. Does any of this scenario make sense?
It may well have been planted by the police and family.
My scenario is this:
Murderer waits outside WHF, then enters when confident that everyone is asleep. Gets loaded and ready gun, plus some spare ammo thats lying placed conveiniently in kitchen. Makes way upstairs, but is disturbed by the awake Sheila.
She's led into parents bedroom, with gun placed under chin. Parents wake, as light is turned on. Sheila is shot in neck, followed by parents. Neville manages to get downstairs followed by killer. Is bludgeoned, then finished off after reloading. Killer goes back upstairs, finishes off June, and puts another bullet into Sheila. Followed by the kids,but they could have been first.
Sheilas right hand and arm has blood on it, as she used this to try to plug first non fatal shot(why plug it if you want to die?).I picture in my mind something similar to the scene in "saving private Ryan", where the guy is shot in the neck, and the American and German fight around him on the floor with a knife.I'd be amazed if she was able to put another bullet in her own neck after the first.
If she did do the killings, why did she choose to take her own life next to the person she disliked the most, i think she'd prefer to do it next to the kids.
Why did she put it under chin, when she showns clinical shooting to the head? Surely in the mouth, or forehead would be a suicide choice?
Anyway people, these are just my thoughts, not really open to debate.