How do you evict people who don't have permission to be living on your property?

[Don't know what to do]

Last August, we moved out of our house so that we could completely gut and re-model our bathroom, we also were re-modeling our living room as well. While out of the house my husband suffered a heart attack. We had an offer from a person who wanted to purchase our home as said he would complete the re-modeling himself.(all materials and fixtures had already been purchased) Until his paper work on the house was approved. With our current situation we thought this was a blessing in disguise. Needless to say this went on for a couple of months and due to problems on his side, we decided that it was taking too long and we would not sell him the home and attempt to do the work ourselves and move back in. Well he moved out, but at some point had brought other individuals in. They refuse to leave and say that they pay rent to the person that owns the home. I have paid my mortgage on my home and all the utilities, and have not recieved anything from these individuals. How do i get them out of my home. Can i legally turn off my utilities? There was no written agreement between me and these people, and I had only a verbal agreement with the person before them. Please help!

You have to evict them in local court if they will not leave; it is easy to do and the court has forms...

[Don't know what to do]

Can I turn my utilites off so that they do not run my bill up any higher?

[Don't know what to do]

Can I turn my utilities off so that they don't run my bill up any higher? Do I actually have to have a court date, or just pick the forms up from my local court house?

You are not supposed to do that normally...but you can sue them for all costs etc.as well in small claims.

[Don't know what to do]

I understand that normally in a normal land lord tenanat situation that would probably not be the thing to do. However they are not my tenants and I don't even know who these people are. So they are tresspassing on private property and "Squatting". So is there not any legal written documentation supporting me the owner, and giving me the right to do what i want to do to my own property? I live in the state of Washington in South King County.
Please advise..