One of my daughters is a police officer, and she said that if someone had called the police and told them that there was a stranger living in her house, the police would probably have thought the person making the report was the nut, rather than the person apparently legitimately installed there. What a Kafkian nightmare!
However, I have heard of this happening elsewhere, and the fact that she was charged with the crime of "home theft" indicates that there is some precedent for this bizarre situation. I guess the moral of the story is to leave a large slavering hound behind you whenever you go on vacation.
This is a strange one. I imagine that drugs in some form or another are involved. I've heard of rental houses being "stolen" in this way, but never a primary residence.