Montana Predominant/Dominant Aggressor

(b) When a peace officer responds to a partner or family member assault complaint and if it appears that the parties were involved in mutual aggression, the officer shall evaluate the situation to determine who is the predominant aggressor. If, based on the officer’s evaluation, the officer determines that one person is the predominant aggressor, the officer may arrest only the predominant aggressor. A determination of who the predominant aggressor is must be based on but is not limited to the following considerations, regardless of who was the first aggressor:

(i) the prior history of violence between the partners or family members, if information about the prior history is available to the officer;

(ii) the relative severity of injuries received by each person;

(iii) whether an act of or threat of violence was taken in self-defense;

(iv) the relative sizes and apparent strength of each person;

(v) the apparent fear or lack of fear between the partners or family members; and