Investigation of applications. The County Department or local governmental unit shall promptly, upon receipt of an application, make the necessary investigation, as prescribed by rule of the Illinois Department, for determining the eligibility of the applicant for aid.
     A report of every investigation shall be made in writing and become a part of the record in each case.
     The Illinois Department may by rule prescribe the circumstances under which information furnished by applicants in respect to their eligibility may be presumed prima facie correct, subject to all civil and criminal penalties and recoveries provided in this Code if the additional investigation establishes that the applicant made false statements or was otherwise ineligible for aid.