Super odd situation with almost no official information. Very curious to see who took Nancy and why. Does not feel like a professional ransom job to me. No proof of life and immediate involvement of the media (no one who kidnaps someone wants a lot of press, they want money), amongst other things.
Additionally, you would have needed to consistently case the residence to pull it off in the peak of darkness. This is a semi-rural area where the homes are on 1-2 acre lots, and everything in the desert tries to poke or kill you. They would have needed hours upon hours of surveillance work. That type of surveillance work would have been seen in a smaller community. Anybody walking their dog would realize someone has been sitting in their car in front of the same house.
Which makes me think… what is this case then? My best guess is a murder by someone close to the family, why - I have no clue. That person then tried to either make it look like a kidnapping by making their pedestrian attempt at a cover up via the ransom letter. Or, someone completely uninvolved was taking advantage of the situation by demanding ransom and just hoping the family paid them some bitcoin.