The proper authorities or persons shall, in their final settlements with the collector, allow him or her credit for the amount so certified. However, if those authorities or persons have reason to believe that the amount stated in the certificate is not correct, or that the allowance was illegally made, he or they shall return it for correction. When it appears to be necessary, in the opinion of those authorities or persons, he or they shall designate and appoint some competent person to examine the collector's books and settlement. The person so designated and appointed shall have access to the collector's books and papers, appertaining to the collector's office or settlement, for the purpose of making the examination.
35 ILCS 200/20-250