State ex rel. Individual v. Davis, 2005 WI 70, on certification
Subpoenaed Individual: Stephen P. Hurley, Marcus J. Berghahn, Hal Harlowe
¶15 A writ of prohibition is an extraordinary remedy that normally will not issue except in the absence of other adequate remedies.  As a remedy, writs of prohibition are often used in connection with John Doe proceedings.  Neither party challenges whether a writ of prohibition is the proper procedure to test the John Doe judge’s authority in the present case. Rather, the parties dispute whether, based on the facts of this case, the court should issue the writ here.¶16 A writ of prohibition is the appropriate remedy “to restrain the exercise of judicial functions outside or beyond the jurisdiction of a court, or an official acting in a judicial capacity, where great hardship would otherwise result.”  Accordingly, if the court or a John Doe judge is properly exercising powers and jurisdiction, a writ will not issue.