§ 144. Power of public welfare officials and service officers to administer oaths; power of public welfare officials to subpoena persons liable for support and compel production of records. Public welfare officials and service officers shall have power to administer oaths and take affidavits in all matters pertaining to their office and to elicit, by examination under oath, statement of facts from applicants for or recipients of assistance or care. Public welfare officials shall have further power to subpoena persons liable by law for the support of applicants for or recipients of assistance or care, compel the attendance of such persons and take their testimony under oath for the purpose of determining the ability of such persons to contribute towards the support of such applicants for or recipients of assistance or care, and in connection therewith to compel the production of books, papers, records and documents. Such persons shall be entitled to the same mileage fees as are allowed to witnesses required to attend in civil actions in courts of record.