Legal Question in Landlord & Tenant Law in Washington

He is a trespasser at this point. You have several options. 1.) Call the police and indicate your former friend refuses to leave your home and you want them to escort him from the premises. The police will inquire of your friend if he lives there. If he says yes, they will likely tell you it's a civil matter, and that they need a court order before they can do anything further. 2.) You file for a restraining order to have him stay a certain distance from you and your home. Say, 100 feet. If you get it, have the police serve it on him, and they will escort him from the premises. 3.) If none of the above works, you have to bring an action for ejectment.

Although self-help is greatly frowned upon in Washington, the reality is that if this person has no claim to be in your home, and they leave, say to go to the store and you lock them out, they will have only legal options to get back in. I caution you, depending on the circumstances, this could really cost you if they prove a right to live in your home.