How do I go about getting someone's belongings out of my house?

My ex-son in law lived at my house for 10 months. He has no mail coming there, paid no rent, no contact. He up and left and took some of his things. There is no bed, no clothes, there are some tools and mostly junk stuff. He is making no effort to get out. I had to pack the basement stuff up as he left it in a terrible mess that looked ransacked. There are things in my garage that are basically keeping me from getting my car into park. How do I go about getting him to remove his belongings? I never charged him for storage.