I'm thinking it through. MOO
If there was something obvious like a gunshot wound to the back of the head, there would be few questions about it being a homicide. They haven't said that. The fact that no one has said anything about any sort of obvious wound, no rumors, etc. makes me believe that either they do not exist, OR the PD runs a WAY tighter ship than has been previously seen.
The mother didn't say anything about blood in the house, no signs of struggle, etc. which you would assume that there would be IF A. this was a violent death and B. that she died in the house.
ETA: A and B can not (most likely) be true together but this does not mean that one or the other of them can not be true. Either she died of something non-obvious at the house, or it was a violent death not at the house. Or, I suppose she died of something non-obvious outside of the house.