Lol.
All the person has to do to avoid arrest is be calm and assertive; if he insists that you invited him, that he paid you rent, that it’s his house, here’s the police response:
“That’s a civil matter, you’re going to have to call a lawyer.”
If he’s competent, he may even have a deed with the town’s seal already in it. Anyone can file anything in the land records. It’s up to title holders to protect their titles and clear any fraudulent entries.
This probably feels like a type of thing that happens much more often than it actually does. But for real I’m going to go check my basement too.