Iowa Code § 915.3: Immunity — citizen intervention.

Any person who, in good faith and without remuneration, renders reasonable aid or assistance to another against whom a crime is being committed or, if rendered at the scene of the crime, to another against whom a crime has been committed, is not liable for any civil damages for acts or omissions resulting from the aid or assistance, and is eligible to file a claim for reimbursement as a victim under this chapter.