The commissioner has the power to issue subpoenas and require attendance of any and all officers, directors, agents, salesmen, collectors, and employees of any association and such other witnesses as he may deem necessary in relation to its affairs, transactions, and conditions, and may require such witnesses to appear and answer such questions as may be put to them by the commissioner, and may require such witnesses to produce such books, papers, or documents in their possession as may be required by the commissioner. Upon application of the commissioner, any person served with a subpoena issued by him may be required, by order of the district court of the county where the association has its principal office, to appear and answer such questions as may be put to him by the commissioner and be required to produce such books, papers, or documents in his possession as may be required by the commissioner.