Inherited Tenant complaining of another tenant smoking weed

[Phil Kagebein]

I recently inherited three tenants in a 3-flat in Berwyn, IL. All were on MTM leases which were just a verbal agreement between the old landlord and the tenants. I have already informed all three tenants I will not be renewing their leases starting August 1st. 

Tenant A has been complaining about Tenant B smoking pot. Tenant A claims they have asthma and can't sleep due to the pot smoke. I asked Tenant B to stop smoking on the property, and was met with a very angry denial that they ever smoked. Clearly asking them to stop isn't going to change anything.

Tenant B now said they are going to city hall against myself and Tenant A. Any advice on what to do in this situation? I can't force people to do anything, especially when their on a verbal agreement and will already be moving out by the end of next month.

Thanks