In an affluent neighborhood I would think every other house has a security system, surveillance camera or door cams, motion detectors etc. At that hour of the night, there has to be some activity, somewhere, some movement captured on video of someone or some car going into or out of the subdivision.
But nothing?
It could be the police/FBI have a very good lead and are watching potential suspects but haven't released that info to the media yet so as to not 'burn' the suspect.
Its hard to believe that there are zero clues.
Maybe the motive isn't ransom. Maybe a family member stands to gain from a life insurance policy and set it up to look like ransom? Or maybe it was ransom but as irongrip says she died during the abduction and they completely panicked.
Was the blood at the scene confirmed to be Nacy's?
Correct me if Im wrong but only one guy was seen on what little video they had but he had an enormous back pack on. Im guessing it contained a tarp, or bodybag, perhaps some burglary tools.
Very odd case.