Before you get all ready to 'go a courtin', you need to read up on the Minnesota Statutes, Chapter 504B about Landlord and Tenant Laws.
For example, did you give the former tenant an written accounting of the security deposit and damages within 3 weeks of moveout (504B.178, Subdivision 3)??? If not, you are in deep ca-ca.
Also, did you pay him interest on the security deposit while you had it??? If not, whoops!
Also, you need to pay particular attention to Subd 7:
"Subd. 7. Bad faith retention. The bad faith retention by a landlord of a deposit, the interest thereon, or any portion thereof, in violation of this section shall subject
the landlord to punitive damages not to exceed $200 for each
deposit in addition to the damages provided in subdivision 4. If the landlord has failed to comply with the provisions of subdivision 3 or 5, retention of a deposit shall be presumed to be in bad faith unless the landlord returns the deposit within two weeks after the commencement of any action for the recovery of the deposit."