A. Shacknai cut her down.
What sort of cord was used around her neck? Seems to me, that if it was an extension cord, those things are thick, and don't take to cutting too easily. So there'd have to have been a huge pair of bolt cutters, or something similar, nearby, for A. Shacknai to have been able to notice her distress, cut her down, run down the stairs, and perform CPR, all while calling 911.
Nothing in this story makes sense. I've been in a few mansions in my time, and neither electrical cords nor bolt cutters are laying in the hallway table drawer...not even in EQ country, and especially not with little folks running around.
My guess?
Max had a bad accident, and it was an accident. J and D Shacknai were at the side of this critically ill boy. Brother flies in from back east, to help attend to matters in the house (taking care of children, running the estate, paying his respects to Max), and, sometime late Tuesday or early Wednesday, raped/killed RN because she was supposed to be keeping Max safe and hadn't, and then staged it to look like a suicide.
That's really the only answer that makes any sense. It's the only thing that accounts for all pieces of the puzzle, that we know of now. It also accounts for the way RN was bound, and found.
'Course, we don't have much info, so I could be all wrong. I've been wrong a lot in the past. LOL.
Best-
Herding Cats