Wis. Stat. § 782.26: Interested person notified.

When it appears from the return to such writ that the prisoner is in custody on any process under which any other person has an interest in continuing imprisonment no order shall be made for discharge until it shall appear that the interested person or attorney, if the person has one, if to be found within the county, shall have sufficient notice of the time and place at which writ is returnable.