Ohio Rev. Code Ann. § 4907.10

Upon demand, the public utilities commission, a public utilities commissioner, or any person employed by the commission for that purpose, may inspect the books and papers of a railroad and examine under oath any officer, agent, or employee of a railroad, in relation to any matter which is the subject of complaint and investigation. A person, other than one of the commissioners, who makes such demand shall produce his authority to make such inspection, under the hand of a commissioner, or of the secretary, and under the seal of the commission.