If the findings of a preliminary investigation give the office of inspector general reason to believe that an incident of Medicaid fraud or abuse involving possible criminal conduct has occurred, not later than the 30th day after completing the preliminary investigation, the office, as appropriate:
(1) must refer the case to this state's Medicaid fraud control unit if a provider is suspected of fraud or abuse involving criminal conduct, provided that the criminal referral does not preclude the office from continuing the office's investigation of the provider that may lead to the imposition of appropriate administrative or civil sanctions; or
(2) may conduct a full investigation, subject to Section 544.0253, if there is reason to believe that a recipient has defrauded Medicaid.