True, Mick, assuming he's ever let out of jail ! As a 'mistake' it doesn't sound very plausible. A man, living in a high-security compound, shoots dead someone in his own house, no questions asked. Does he not turn the lights on? Does he not shout to find who's there? On what basis did he think a) it must be a burglar b) he's armed c) I am being threatened?.
Does this woman not live with him? If so, did he not wonder why she didn't say anything (" I heard a noise") or where she had gone?
If she doesn't live with him , we take that she has free access; she doesn't have to break in but has a key or the codes to enter the site and house. And she's taken in to her head to enter at 4 a.m, and ,evidently, without so much as calling out.. Hmm