In a "domestic dispute", an individual was charged with Assault IV and taken to jail due to biting her attacker in self-defense. The officer told her that no matter what the circumstance, it meant a mandatory arrest in either the State of Oregon or Multnomah County; unsure which. The two parties involved told greatly conflicting stories (of course), but the attacker, who is 6'3" and 220 lbs. was not arrested while the person who bit him is 5'3" and 120 lbs. She was taken to jail although she had been beaten and choked. This mandatory rule / law seems elusive despite research. Is this true?