The director may, under his or her hand and official seal, appoint such special deputies or assistants as he or she may find necessary for the efficient and economical liquidation of insolvent banks, with powers specified in the certificate of appointment, to assist him or her in the liquidation. The certificate shall be filed with the director and a certified copy with the clerk of the district court of the county in which the main office of such bank is located. He or she may also employ such counsel and expert assistance as may be necessary to perform the work of liquidation. He or she shall, subject to the approval of the district court of the county in which the main office of the insolvent bank is located, fix the compensation for the services rendered by such special deputies, assistants, and counsel, which shall be taxed as costs of the liquidation. He or she may discharge such special deputies, assistants, or counsel at any time or may assign them to one or more liquidations or transfer them from one liquidation to another.