Arizona Revised Statutes Title 13. Criminal Code § 13-406. Justification; defense of a third person

A person is justified in threatening or using physical force or deadly physical force against another to protect a third person if, under the circumstances as a reasonable person would believe them to be, such person would be justified under § 13-404 or 13-405 in threatening or using physical force or deadly physical force to protect himself against the unlawful physical force or deadly physical force a reasonable person would believe is threatening the third person he seeks to protect.