Tenants trying to break lease due to roaches after 1 month

[Michael Miller]

My tenants moved in late August and after about a week they found there were roaches in the unit. Previous tenants had seen some but we got pest control to treat it and it wasn't a major issue. The building has never had a real roach issue before.

I got pest control to treat the unit as soon as I heard about the issue. After a week, they were still having issues so I had pest control come back again, though they notified me it was likely a building issue. I raised it to the board of the HOA the following Monday (now 3 weeks into the lease) and we agreed to have our base pest control enhanced to take care of the issue. I offered my tenants a 50% rent reduction until the issue was resolved (rent was already WELL below market). They have been adversarial throughout the process and are now insisting they break the lease and move out by next week. Do I have any reason to return the security deposit / any defense if I choose not to? Tenants have threatened getting the county/property attorney's involved but frankly they don't strike me as very sophisticated so I have my doubts. FYI, the unit is in MN.