Dogs are not liable; their owners are.
Most, if not all, states have statutes regarding the destruction of dogs attacking humans or livestock. Review the facts with an attorney familiar with animal law in NY.
The foregoing is for general information purposes and does not establish an attorney-client relationship.
As a very general statement, there are circumstances where it is legal to kill a dog that is posing a threat to an individual or livestock. I would consult a local attorney about the circumstances in your state. Merely "threatening" and "being off leash" may not enough.
This is not to be construed as legal advice. I do not have an attorney client relationship with you.
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