Wis. Stat. § 898.05: Interrogatories.

The plaintiff in the action may, upon such examination, propose to the prisoner any interrogatories pertinent to the inquiry and they shall, if required by the creditor, be proposed and answered in writing and the answers shall be signed and sworn to by the prisoner; and the plaintiff in the action may have a copy of the interrogatories and answers certified by the officer before whom such examination is had, upon paying therefor the legal fees.