Editor's Note: the following is a follow-up article to the shiur available here.
The prohibition of mesirah is well known among religious Jews. The severity of this issur becomes ever so clear when we read in Shulchan Aruch that a mosser is dino ke'akum with respect to writing a sefer Torah (Yoreh Deah 281:3) and with respect to shechitah ( Ramoh ibid 2:9). Even if the mosser is otherwise an observant individual, and is meticulous in fulfilling his religious duties, because he demonstrates his rejection of the unity of all of Klal Yisroel (by his act of mesirah), he is treated as an akum (see Rambam, Hilchos Teshuva 3:11 and Nefesh Horav pg. 235).
If, however, one is guilty of a crime, and according to the law of the land deserves a prison sentence, or will be put to death, even though according to Jewish law his punishment would not be as severe, this is not mesirah (see Ritva to Bava Metsia 83b; Dvar Avraham vol. I pg. 8). One would still not be allowed to hand this individual over to the civil authorities because this is the equivalent of returning aveidas akum, which is usually not allowed. In an instance of avoiding a chilul Hashem, just like we would be obligated to return the aveidas akum, so too we would be obligated to hand over this individual (see Ramoh, Choshen Mishpat 388:12).
If the non-Jewish governmental authorities know that one Jew is concealing information about another Jew in order to save him from punishment, the Shulchan Aruch (Choshen Mishpat 28:3) considers this a situation of chilul Hashem. Similarly, for many generations it was the practice that if a gneiva had occurred, and suspicion had fallen on the Jewish community, rather than allow that suspicion to hover over the entire community, the roshei hakehol, with the permission of the rabbonim, would inform the non-Jewish authorities who might possibly be the real ganav (Be'er Hagola, Choshen Mishpat 388:12).
Even if one is guilty of a crime and deserves a punishment according to the laws of the land, but due to anti-semetic attitudes he will probably suffer more than if he were a non-Jew; or, the (state) prison conditions are such that he will suffer at the hands of the other inmates (or at the hands of the guards) in a manner that is not prescribed by law, then turning the offender in would constitute mesirah, since his added suffering will be shelo kadin. However, mesirah is permitted in situations where one is a public menace (see Shach to Choshen Mishpat 388, 59), or if one is physically or psychologically harming another individual (for example, in instances of sexual abuse of children, students, campers etc., or spousal abuse) (see Shach to Choshen Mishpat ibid, 45).
The Jewish community does not have the ability to investigate these types of cases. Wherever there are raglayim ladavar that there seems to be a problem, the proper government agencies should be contacted to investigate.
Just as in other areas of halachah, one should consult a competent moreh horaah when faced with such a shayla. Just because one is knowledgeable in Yoreh Deah vol. I or one delivers a good pilpul shiur on sugyos in Nashim or Nezikin, it does not necessarily follow that that individual will be qualified to pasken on hilchos mesirah - lehakel or lehachmir.