Legal Question in Landlord & Tenant Law in Missouri

Unless they have a valid lease, you can give them a written Statement terminating their tenancy, and a date that they must be out. If they aren't out, you can file suit for rent & Possession, or one for unlawful detainer ((depending upon which fits the facts of the situation. ) You will likely be me successful having an survey handle it fit you, as landlord who do it wrong can wind up owing money to a deadbeat tenant.

Good luck