A Wisconsin Subpoena in a Criminal Case — AO 89 is a court document that is issued by a judge or magistrate in Wisconsin ordering someone to appear in court to provide testimony or produce evidence related to a criminal case. It can also be used to obtain documents or other records. There are two types of Wisconsin Subpoena in a Criminal Case — AO 89: SubpoenDuckseCecumum (to produce documents or other records) and Subpoena Ad Testificandum (to appear in court to give testimony). Both types of Wisconsin Subpoena in a Criminal Case — AO 89 must be served on the person or entity being subpoenaed prior to the hearing date in order to be valid.