Had the misfortune of having a tenant's relative staying in my rental and their discarded cigarette caused a serious fire. The house will be gutted down to the studs and outer walls and rebuilt. Thank goodness for insurance and rental income replacement clauses! I have withheld the damage deposit and last month's rent from the tenant (which they want back) on the basis that the 'guest' was not approved by me (lease states anyone over 14 days must be approved in writing) and that the tenant is responsible for damages caused by her guests. Also, just days before the fire, I suspected there was someone else staying at the suite and specifically asked the tenant to make sure the door was locked and that no one else had the key. Tenant ignored me and gave the guest keys. Also noteworthy is that the tenant had changed the lock and failed to actually give ME a key, which again points to questionable motives. I'm assuming that I'm within my rights with the damage deposit but can I withhold returning any of the last month's rent too? (This is in AB) Is there any way they have a case as they are planning to go to the LTDRS?