(C) For the purpose of conducting such a hearing the chief may require the attendance of witnesses and the production of books, records, and papers, and the chief may, and at the request of any person having a direct interest in the matter being heard, the chief shall, issue subpoenas for witnesses or subpoenas duces tecum to compel the production of any books, records, or papers, directed to the sheriffs of the counties where such witnesses are found, which subpoenas shall be served and returned in the same manner as subpoenas in criminal cases are served and returned. The fees of sheriffs shall be the same as those allowed by the court of common pleas in criminal cases. Witnesses shall be paid the fees and mileage provided for under section 119.094 of the Revised Code. Such fee and mileage expenses shall be paid in advance by the persons at whose request they are incurred, and the remainder of such expenses shall be paid out of funds appropriated for the expenses of the division. In case of disobedience or neglect of any subpoena served on any person, or the refusal of any witness to testify to any matter regarding which the witness may be lawfully interrogated, the court of common pleas of the county in which such disobedience, neglect, or refusal occurs, or any judge thereof, on application of the chief, shall compel obedience by attachment proceedings for contempt as in the case of disobedience of the requirements of a subpoena issued from such court or a refusal to testify therein. Witnesses at such hearings shall testify under oath, and the chief may administer oaths or affirmations to persons who so testify.