Washington Revised Code Title 9. Crimes and Punishments § 9.01.055. Citizen immunity if aiding officer, scope--When

Private citizens aiding a police officer, or other officers of the law in the performance of their duties as police officers or officers of the law, shall have the same civil and criminal immunity as such officer, as a result of any act or commission for aiding or attempting to aid a police officer or other officer of the law, when such officer is in imminent danger of loss of life or grave bodily injury or when such officer requests such assistance and when such action was taken under emergency conditions and in good faith.