Landlord should not be involved with disputes between tenants, unless the dispute escalates into criminal acts, such as battery and/or assault. This is the exception that proves the rule that Landlord should generally not get involved.
The difference between battery and assault is that battery requires physical touching, e.g. the fist has to land on the victim. Assault requires only comprehension of attack， e.g. the fist swung and missed the victim, a crime still occured, it is an assault but not battery.
After a criminal act is commited, the landlord should evict, failing doing so would open the landlord to possible liabilities.
