Madeleine,
It depends on your hypothesis. If you are inclined to the side that no matter what BC did it, then no, an alternate hypothesis carries little weight.
On the other hand, if your inclined to be unsure at this moment that BC did it, then you add up stuff on that (BC may not be guilty) side of the ledger:
Crime committed, but no crime scene could be determined or found in the house.
No forensic evidence BC transported a body.
ME conclusions weak as to TOD. Could be hours before 7 am or after 7 AM.
Forensic Bug Guy left the window open as equally before or after 7 AM.
6:40 AM phone call: spoofed by BC, or made by unknown third party, or made by NC herself is inconclusive.
So if not BC then who??? Yes, I know it could be BC, it should be BC because he's a slimeball, and most folks here want it to be BC.
But for just a moment, think: what if it's not BC, and postulate for the briefest time that he is maybe being framed by a killer.
Does that mean he did not do it. No, it just means keep your mind open, explore all possibilities, and after all evidence is heard, explored and trashed over, the jury will speak, affirmatively one way or the other.
Then we will all know......