1. The commission may subpoena witnesses. All subpoenas shall be signed and issued by a commissioner or by the secretary of the commission, and shall extend to all parts of the state, and may be served by any person authorized to serve process of courts of record or by any person of full age designated for that purpose by the commission or by a commissioner.

2. The person executing any such process shall receive the fees now prescribed by law for similar services in civil cases in the circuit courts in this state, and shall be paid in the same manner as provided herein for the payment of the fees of the witnesses.

3. Each witness who shall appear before the commission or a commissioner by its or his order, shall receive for his attendance the fees and mileage now provided for witnesses in civil cases in the circuit courts of this state, which shall be audited and paid by the state in the same manner as other expenses of the commission are audited and paid, upon the presentation of proper vouchers sworn to by such witnesses and approved by the commission.

4. Whenever a subpoena is issued at the instance of a complainant, respondent, or other party to any proceeding before the commission, the cost of service thereof and the fee of the witness shall be borne by the party at whose instance the witness is summoned.

5. Any witness subpoenaed except one whose fees and mileage may be paid from the funds of the commission, may, at the time of service, demand the fee to which he is entitled for travel to and from the place at which he is required to appear, and one day’s attendance. If such witness demands such fees at the time of service, and they are not at that time paid or tendered, he shall not be required to attend before the commission or commissioner, as directed in the subpoena. No witness furnished with free transportation shall receive mileage for the distance he may have traveled on such free transportation.