Worst case scenerio for the WTS, or more aptly put, the local elders:
IF, IF, they knew that Holt had viewed or owned child porn (which I doubt. If they had known that, they probably would have taken measures to DF him.) then those local elders could face charges, IF, again, IF, state law requires reporting of such a crime. Too many IFs. And even then, the WTS would distance themselves from those elders, because they did not follow procedure and call legal to get proper instructions. Those local elders would be left to swing on their own. So, the elders get the shaft and face charges, the WTS walks off clean.
But it ain't gonna happen. This is too much of an open and shut case for prosecuters. They don't need to muddy up the waters with conspiracy theories of how church leaders covered up Holt's being unstable and possibly dangerous.
Oregon does have the death penalty and the young Mr. Holt is the prime candidate for recieving that sentence. Physical evidence, admission of the crime. The only defense he'll have is temporary insanity, which I'm sure his legal team will use, just to keep him for getting the death penalty.
Forget civil trials. From the family's responses so far, it is pretty clear that they are heavily indoctrinated. They would never consider that the WTS, or local elders, have any culpability in the matter. This was an attack from Satan, in the form of a twisted, demonized ex-member of their congregation. And quite frankly, I don't really think the elders are culpable either. Even if they knew he viewed/owned porn, even more sadistic foms of it, there's no way to know that he would go and kill. Elders can't be like thought police, or oracles that can see the future, or see future crimes. Judicial committee meetings aren't like Minority Report.