which state?

Many state has one bite rule, that the owner is not responsible for the dog's first bite because he had no knowledge of dog's tenencies.  But subsequent second bite would trigger liabilities and even result in forceable death of the dog.  Check your state law on this issue. 

Same applies to the landlord, that you had the knowledge of the first bite, and you didn't do anything to resolve the risk to community.  That's your liability. 

Your possible defense is that you had no power to remove the dog/tenant because they had a certificate for service animal or emotional support animal  AND your state law prohibit denial of service/emotional support animal, again, check your state law. 

 

This is what you should tell the HOA and the lawyer.  That you could not evict.