In all hearings and proceedings before the commission, the evidence of witnesses and the production of documentary evidence may be required. Summons may be issued by it for appearance at any designated place of hearing. In case of disobedience to a summons or other process, the commission or any party to the proceedings before the commission may invoke the aid of any circuit court in requiring the evidence and testimony of witnesses and the production of papers, bonds and documents. Upon proper showing, the court shall issue an order requiring witnesses to appear before the commission, produce all books and papers, and give evidence touching the matter in question. Any person failing to obey the order may be punished by the court as for contempt. A claim that evidence may tend to incriminate the person giving the evidence shall not excuse him from testifying, but he shall not be prosecuted for any offense concerning which he is compelled to testify.