The problem with allegations this bizarre tends to be that that they are so outlandishly weird no one usually can believe them. Does that mean nothing criminal happened? Not necessarily.
If such crimes occurred with the perpetrators as actual clergymen, as alleged, it starts to make you wonder whether some form of diabolical possession is involved. One would certainly want hard evidence to back up such claims of cult crime.
What investigators should be looking for in such cases are details in the backgrounds of the accused which could link them with the occult or extreme sex (S&M porn, etc.). It is important for the purposes of understanding this kind of bizarre, criminal counter-culture to determine whether any of those accused were involved with such activities BEFORE they became clergymen. If such allegations are true, it would seem likely that such individuals would be connected with activities OUTSIDE of the ecclesiastical institutions as well. Just because someone joins a Catholic organization does not necessarily mean that is the main focus of their life. Insanely psychotic people and people with warped, twisted emotional development exist. Still, these allegations are very weird.
But mere affiliation with the church does not always mean that a person is free of criminal tendencies. And the devil stalks consecrated souls as well. The possibility that real supernatural evil is present is something that some investigators have difficulty dealing with. For one thing, it's NOT a human mind that is directing such activities.
I would think he would do so with particular intensity -- whenever anyone gives him the chance.