How about solving the problem of Sheilas' prints all over the shotgun ? What was she doing with it because she didn't use it to shoot anyone ? Maybe as a threat at first ?
How do we know that Neville used the downstairs phone when he rang Jeremy ? Seeing as he " was in bed " ,did he use the office phone ? NOBODY KNOWS,do we ? !
This all kicked off upstairs in the bedroom--------not the kitchen,though ended up there when Neville had attempted to go downstairs followed by Sheila,prodding him.
The light was on in the main bedroom all the time,so quite easy to have seen a silhouette from outside as WAS SEEN,contrary to what others say.
I very much doubt that Jeremy would have started switching all the lights on in order to murder all the family. That's another ludicrous and far-fetched assumption. Why would he have needed the lights on ?