In case any witness shall fail or refuse to obey any subpoena issued by the commission, or to produce before the commission such books, papers, documents or records as shall have been enumerated and required in any subpoena, or shall fail or refuse, when before the commission, to give testimony lawfully required by it, or fail or refuse to answer such questions as may be propounded by it which such witness would be required to answer if in court, he shall be guilty of a misdemeanor, and upon conviction thereof, for each offense, shall be fined in any sum not exceeding five thousand dollars. The claim that any such testimony may tend to incriminate the witness shall not excuse the witness from testifying, but such evidence or testimony shall not be used against such person on the trial of any criminal proceeding. Testimony may be taken by deposition as in suits at law. Witness fees shall be paid as provided by law in attendance at any district court in this state. The sheriff or constable executing any process of the commission shall receive such compensation as is provided by law for performing similar services.