I’ve seen people do some crazy stuff on booze. And being a young lady like that someone could have slipped her some drugs in a drink.
Supposedly passengers saw this girl and one of her stepbros at the theater prior to her death. They said they appeared to be in a heated argument.
I am guessing he had a thing for her and she refused him.
I think the autopsy will clear a lot of this up. Was she clothed? Was she suffocated or strangled? My guess is no blood visible because there would be no use stuffing her under the bed if it wasn’t cleaned up.