Oregon Revised Statutes Procedure in Criminal Matters Generally § 133.225

(1) A private person may arrest another person for any crime committed in the presence of the private person if the private person has probable cause to believe the arrested person committed the crime. A private person making such an arrest shall, without unnecessary delay, take the arrested person before a magistrate or deliver the arrested person to a peace officer.

(2) In order to make the arrest a private person may use physical force as is justifiable under ORS 161.255.