When, in any divorce proceeding or upon request for modification of a divorce decree, an allegation of child abuse or child sexual abuse is made, implicating either party, the court shall order that an investigation be conducted by the department of health and welfare. A final award of custody or visitation may not be rendered until a report on that investigation is received by the court. That investigation shall be conducted by the department within thirty (30) days of the court’s notice and request for investigation.