ITA, I find it unusual the FBI would go in 'camera's ablazing' knowing that the media was camped out in front of the home. I believe it is possible to have been a staged event to throw off someone(s). I remember seeing this happen in one other case - The Kelsey Berreth/Patrick Frazee case and they were much, much more discreet.
If this was an actual CS investigation at AC's home, does anyone know if they all returned to AC's there after dinner? If they did and hung out a bit, maybe something did happen there (an unplanned argument or disagreement) and Nancy was driven home. Garage door opens close to 11 pm.
<Crazyland Scenario Speculation>
Nancy wouldn't have to have been alive at the time she was dropped off, she could have just been placed in the home and then someone(s) returned and staged the scene and dreamed up this crazy kidnapping for ransom scenario. Garage door wouldn't show opening again if someone had keys and entered and exited the front door.
I find it hard to believe it was any family member.. This case makes my head hurt.
Still holding out hope that Nancy is found alive and reunited with her loved ones.
JMO