42 C.F.R. § 457.915
(a) State program requirements. The State must establish procedures for ensuring program integrity and detecting fraudulent or abusive activity. These procedures must include the following:
(2) Methods for investigating fraud and abuse cases that—
(c) Program coordination. The State must develop and implement procedures for referring suspected fraud and abuse cases to the State program integrity unit (if such a unit is established) and to appropriate law enforcement officials. Law enforcement officials include the—