Conduct hearings and investigations in connection with the administration of public aid; compel by subpoena, the attendance and testimony of witnesses and the production of books and papers; and administer oaths to witnesses. No person shall be compelled to attend an investigation or hearing at a place outside the county in which he resides.
     Subpoenas may be served as provided for in civil actions. The fees of witnesses for attendance and travel shall be the same as the fees of witnesses before the Circuit Court and shall be paid as an expense of administration.
     Any qualified officer or employee of the Department designated in writing by the Director may conduct the hearings and investigations.