My ex husband was on a review panel for behavioral health complaints in his state for ~6 years. He left resigned ~2 years ago. He also says that anonymous complaints NEVER get investigated. If the situation is so outrageous and someone is in harms way, mandatory reporting laws are meant to deal with the issue. But, when it comes to clients, other therapist or friends, neighbors and family of the client reporting anonymously it get regulated to the back file, then to be moved onto the trash. He has always stated that there is not enough resources to do justice to the cases that they already have all the names and cooperation of the alleged injured party(s).