Require doctor's prescription and current vaccination records.

My suspicion is this tenant went to a doctor or counselor, received a prescription, and then never returned for treatment.

If a person within your unit has a prescription or documentation from a medical person or therapist that says the person needs a service/assistance/comfort animal, you cannot prevent the tenant from having the animal—even if you have a no-pet policy.

In fact his only real prescription has been medication.I feel this problem is yours to figure out, not the landlord.

When you go to the CVS Pharmacy to pick up a prescription do you sometime pick up some laundry detergent on the way out even though it costs twice as much as at the grocery store?  

It strikes me that the clear intention of the legislature was to clear title on tax deeds after four years, but the wording of the statute unfortunately leaves wiggle room: "A title under a tax deed properly executed on or after July 1, 1996, at a valid and legal sale shall ripen by prescription after a period of four years..."

Items go on the curb, the landlord is NOT required to store anything (except prescription medicine or prescription medical equipment which must be held 7 days from the date of discovery). 

If the disability is not obvious we ask for documentation of the prescription.  

This is a 4 unit apartment building in MinnesotaMy tenant was on assistance and was on a lot of prescription drugs.

You CAN (and should) get an additional deposit.You are allowed to request proof of prescription - a valid Emotional Support Animal (ESA) is prescribed by a physician.