Wis. Stat. § 885.07

Every witness on behalf of the state in any civil action or proceeding may file with the clerk of the court where the same is pending the witness’s affidavit of attendance and travel, and the witness’s fees shall, upon the certificate of such clerk, countersigned by the attorney general, district attorney, or acting state’s attorney, be paid out of the state treasury, and shall be charged to the legal expense appropriation to the attorney general. In forfeiture actions by municipalities the clerk shall tax witness fees; however witness fees for police officers of any such municipality when collected shall be paid by the clerk to the treasurer of the municipality.