My take on the dog closed in a closet/kennel. It was a German Shepherd, and probably trained for security purposes due to their age and remote location.
We have a seven pound Biewer Yorkie and when someone comes he can become noisy and aggressive, the first thing we do when we are expecting someone is put him in his crate. I think that is a big clue, they were expecting someone.
MY ROTT mix I got from the pound will imitate CUJO until you give him a bone-—
THAT is the ‘price of admission’
Then he becomes a pest for more attention.
Excellent point. That scenario might also explain why a door was open.