I’m not really sure. I don’t know what California law says about duty to report crimes, especially sexual offenses, against minors, and more importantly what it said at the time.
Absent a specific crime that California created, unfortunately, I don’t see a violation of criminal law. The reason is that – surprising to many people – there is no general duty to report a crime. So if you became aware of a crime and fail to report it, you aren’t generally breaking the law.
Perhaps the most in-your-face, horrifying example of this was the sexual assault and murder of seven-year-old Sherrice Iverson by Jeremy Strohmeyer. Strohmeyer lured Sherrice into a casino restroom, molested her, and killed her. His friend David Cash witnessed the crime – actually saw Strohmeyer grabbing and fondling Sherrice in te restroom. Cash left; Strohmeyer followed twenty minutes later and confessed he had killed the girl. Cash did nothing.
After Strohmeyer was identified by casino cameras and arrested, there was an outcry for Cash to be punished in some way as well. After extensive investigaton, the authorities concluded that his conduct was simply not illegal.
The case did lead to the state passing a new law requiring that anyone with reasonable suspicion that a child younger than 18 is being sexually abused or violently treated must report it.
So Mahoney not reporting the crimes, and even continuing to reassign offenders to different parishes, is not a general criminal act. If there’s real interest, I’ll try to dig up California law, then and now, for more detail.