There  is a communal back door in the property that was always locked, now the landlord has removed the lock, so anyone can exit the building and things are being stolen  from the garden  is there any way the door could have a combination lock for tenants to exit, and then be alarmed in the event of a fire? kindest regards, Eileen 

If this door is required for means of escape then it needs to be accessible at all times, from the inside, the building is occupied, it could be fitted with an alarm to tell the tenants  that some person has opened it, so it could be investigated.