Someone who is working in fprgeries and there is reason to be afraid that he will thereby endanger the public, his law is the same as that for someone pursuing [another to kill him] and and we warn him not to do it. If he isn’t influenced, it is permissible to hand him over to the government and say, “No one else is working in this but so-and-so alone.” Similarly an individual that the community is libeled on account of him, he could say to them [the government, “I do not do this; only so-and-so alone [does].”

While in general it is prohibited to turn another Jew in to the government, it may be done to protect the community. Moreso, since we are told that he has a law of a “rodeif“, a potential murderer, in cases where his behavior risks lives we are OBLIGATED to do so.

This includes child and spouse abusers.