(a) The Department shall be the sole agency responsible for receiving and investigating reports of child abuse or neglect made under this Act, including reports of adult resident abuse or neglect as defined in this Act, except where investigations by other agencies may be required with respect to reports alleging the abuse or neglect of a child by a person who is not the child’s parent, a member of the child’s immediate family, a person responsible for the child’s welfare, an individual residing in the same home as the child, or a paramour of the child’s parent, the death of a child, serious injury to a child or sexual abuse to a child made pursuant to Sections 4.1 or 7 of this Act, and except that the Department may delegate the performance of the investigation to the Illinois State Police, a law enforcement agency and to those private social service agencies which have been designated for this purpose by the Department prior to July 1, 1980.
     (b) Notwithstanding any other provision of this Act, the Department shall adopt rules expressly allowing law enforcement personnel to investigate reports of suspected child abuse or neglect concurrently with the Department, without regard to whether the Department determines a report to be “indicated” or “unfounded” or deems a report to be “undetermined”.
     (c) By June 1, 2016, the Department shall adopt rules that address and set forth criteria and standards relevant to investigations of reports of abuse or neglect committed by any agency, as defined in Section 3 of this Act, or person working for an agency responsible for the welfare of a child or adult resident.