By Sheilas' own admission to Doctor Ferguson,,she told him how fearful she was that the twins would kill her,,or her own fear that she would kill them. I'm surprised that the doctor dismissed both these terms of speech which are very real when the patient happens to suffer from a debilitating mental illness. What Sheila had said should have been taken as a " threat " because if I'd been the doctor after events unfolded at the farmhouse,I'd have said straight away without a shadow of a doubt,that Sheila had committed the murders while in a psychotic state.
The doctor even admitted himself that the mention of the twins being fostered would have " tipped her over the edge ".
Sadly,this case only points one way,and that's to poor Sheila with her tortured mind. If only the system hadn't let her and her family down. Because it did,,,abysmally.