Idaho Code § 19-3007: Service of subpoena.

A subpoena may be served by any person, but a peace officer must serve in his county any subpoena delivered to him for service, either on the part of the people or of the defendant, and must, without delay, make a written return of the service, subscribed by him, stating the time and place of service. The service is made by showing the original to the witness personally and informing him of its contents.