I wasn't discounting criminal negligence when I discounted criminal activity. There is a lot of talk here about this being a premeditated homicidal act, and it doesn't seem to have been that.
Obviously anything can still come out, but there are patterns to cases in which parents, or caretakers, murder children, and this case isn't an especially good fit.
When a parent goes nuts and starts killing children it is more typically a situation in which the parent who has just lost out on custody issues or has been kicked out of the home, goes back where he is not supposed to be and commits crimes.
I say, "He," because it is usually, not always of course, but usually the man, meaning the biological father, who commits the crime because the mother has custody of the children: "If I can't have my woman and my children, no one can have them."
The person who has been kicked out of his house, out of the marital bed, and out of his children's lives has the most obvious motive.
That's the profile for these crimes, so the police have exonerated completely the father, right?
If he wasn't involved, then it was the mother, the contractor or the grandfather. We can exclude the grandfather from premeditated murder, correct? That wouldn't make sense.
Now it might have been he who cleared out the fireplace. Does anyone know who was supposed to have done that?
So if it was murder, then it is the mother or the contractor.
Crimes like that happen, but there almost always some other contributory pathology at work. It can be drugs, mental illness, greed (for the insurance money), or simply wanting to be left without the responsibility of children.
None of those factors have been brought forward, right? That might still happen. But so far the common sense evaluation is that there was a terrible misunderstanding of the dangers of embers, perhaps exacerbated by alcohol or sleep, rather than anything premeditated.