Complex sentence: The advocacy group, Advocates for Children in Therapy has stated that its three leaders (Jean Mercer, Larry Sarner, and Linda Rosa) were directly involved in prosecution of the Candace Newmaker case.
Split into simpler sentences: The advocacy group, Advocates for Children in Therapy has stated that it was involved in the prosecution of this case. The group reports that its three leaders (Jean Mercer, Larry Sarner, and Linda Rosa) were directly involved in prosecution of the Candace Newmaker case.