If I had to guess it would be some type of drug and/or extreme intoxication.
It might have been the salmon mousse.
That was during that insane arctic blast. Probably drunk, walked out in the backyard to piss. Find the door locked behind them somehow. Dead/unconscious in 15 minutes or so.
“If I had to guess it would be some type of drug and/or extreme intoxication.”
Could possibly account for the deaths but what accounts for the man leaving them outside dead and not calling authorities and claiming to be totally ignorant of the whole thing?