Tenant without a contract

[Peter Chen]

Hi,

I'm sure this is a topic that most have not encountered because of basic due diligence before renting a property.  I have a homeowner who was ready to lease a room in a house to a renter and asked the renter to fill out the proper rental agreement paperwork.  The prospective renter was asked to bring the completed paperwork on the day of the move-in.  On the move-in date, the prospective renter appeared at the house and the homeowner allowed that person to move in.  After moving in, the homeowner asked for the completed rental agreement and an ID, which the prospective renter refused to provide.  Now that person refuses to leave.  

What are the suggested course of action?

Thanks!