Gemara

(Ameimar) Question: (It was enacted that if it is clear that Levi stole from David, but it is not known how much, David swears how much was taken and he collects.) Was a similar enactment made regarding a Moser (Ploni incited the government to take Yakov's property)?

The opinion that exempts for Garmi (causing damage), surely exempts. We ask according to the opinion that obligates for Garmi. Can Yakov swear what was taken from him and collect from Ploni?

This question is unresolved.

117a: Yosef wanted to show Yehudah's straw (to extortionists). Rav told him not to. He persisted 'I will show'.

Rav Kahana broke Yosef's neckbone.

Rav: "...Like a trapped wild ox" - once a wild ox is trapped, no one has mercy on it. Similarly, once money of Yisrael falls into the hands of Nochrim, they have no mercy on it.

119a (Rav Huna or Rav Yehudah): One may destroy property of a Moser.

Since one may kill him, all the more he may destroy his money!

(The other of Rav Huna and Rav Yehudah): One may not destroy his property.

Perhaps he will have a righteous heir - "the Rasha prepares, and the Tzadik will wear (benefit from it)."

Sanhedrin 57a (R. Avahu): We throw into a pit Mumarim (people who sin to anger Hash-m), Mosrim... We do not raise them.

Rishonim

Rif (Bava Kama 46a): Amora'im argued about whether or not one may destroy property of a Moser. Elsewhere, the Gemara forbids. I.e. we did not settle whether or not there was an enactment to swear and take from him what one lost (62a), all the more so one may not destroy his property!

Rosh (Bava Kama 10:34): This is not a solid proof. Perhaps the question about the enactment refers to a Moser who repented!

Rambam (Hilchos Chovel u'Mazik 8:11): If a Moser carried out his plot, it seems to me that one may not kill him unless he is established to be Moser. Then, we kill him lest he be Moser others.

Magid Mishneh: Avodah Zarah 26b teaches that we kill established Mosrim.

Rivash (238): Letter of the law, a Moser should not be killed. A murderer is killed only if he himself killed, but not for inciting a dog or snake to bite and kill someone. Edim Zomemim are not killed after the victim was killed. It is a Chidush that we kill them if they were Huzam after the sentence and before execution. All the more so a Moser is exempt, especially if he only was Moser money. He is killed like a Rodef, for the sake of the future, to save the victim. If he already was Moser, Beis Din punishes him according to letter of the law for what he did, or more, for a fence (to deter others), according to the needs of the time. If he is habituated to do so, i.e. has done so three times, he is like a Rodef, and anyone can kill him anywhere at any time, with or without Beis Din, to save others. The Rambam permits overtly killing him. R. Chananel permits only to cast him into a pit so he will die there, but not overtly killing him. Even R. Chananel would to giving him to officers of the kingdom to kill him, for this is not overt. Also Teshuvas ha'Rosh says so.

Rosh (Teshuvah 17:2): If one was already Moser, and there is fear lest he do so again, some permit hiring Nochrim to punish him. Some forbid, for if a Rasha was Mekadesh 'on condition that I am a Tzadik', we are concerned lest he repented. The first opinion says that this is a mere stringency of Kidushin. R. Ami did not save a man from death because people testified that he ate Isur to anger Hash-m (Gitin 47a). He was not concerned lest the man repented!

Yam Shel Shlomo (ibid.): I say that killing through a Nochri is like overtly killing. We are stringent to say Yesh Shali'ach l'Davar Aveirah through Nochrim. The Gemara permits only lowering to a pit. Perhaps he will repent there and convince us that he will not do so again. If so, we take him out. Presumably, one may hire Nochrim only when there is concern lest he be Moser. Then, one may kill him overtly. It is slightly better through Nochrim if there is no concern lest this cause other problems.

Question (Beis Yakov 2, cited by R. Akiva Eiger 388:15): We are stringent to say Yesh Shelichus l'Nochri, but since Nochrim are liable for murder, Ein Shali'ach l'Davar Aveirah for murder! Perhaps the Maharshal holds like the Tasbatz and Rema (388:15), who say that Yesh Shali'ach l'Davar Aveirah if the Shali'ach is established to transgress. The Beis Yosef says in the name of the Tashbatz that Ein Shali'ach l'Davar Aveirah applies only to Yisrael. However, in EH (5:14), the Rema rules like the Terumas ha'Deshen that Ein Shali'ach l'Davar Aveirah applies to Nochrim.

Poskim

Shulchan Aruch (388:11): If a Moser carried out his plot, one may not kill him unless he is established to be Moser. Then, we kill him lest he be Moser others.

Mordechai (Bava Kama 196): R. Simchah proves that the Rif disagrees. The Rif proved that we may not destroy property of a Moser from the unsettled question about an enactment to collect from a Moser, which discusses after he was Moser. The Amora'im argue about whether or not we make a Kal va'Chomer, but all agree that one may kill him!

Rebuttal (Yam Shel Shlomo ibid.): Why didn't R. Simchah ask about the Rambam, who forbids destroying a Moser's money, even though he forbids killing him after he was Moser! Rather, the Rambam distinguishes between before and after only regarding killing, but the one who permits destroying his money permits even afterwards. One may kill a Rodef who seeks to rape a man or Ervah only before the act. If we permit destroying his money, this is a fine, and it is even afterwards. This is why the Rif learned from 62a. Most forbid destroying his money.

Note: It seems that R. Simchah's proof was not from the Rif's rulings, rather, because the Rif learned from the question about the enactment. The Shach (55) says that the opinion of the Rif, like R. Simchah explains, is primary. Tosfos and Piskei ha'Tosfos agree. However, many follow the Rambam.

Lechem Sesarim (cited by R. Akiva Eiger): What is the proof that the Rif argues? Perhaps he permits killing one who was established to be Moser! Rather, the question was even about one who was Moser only once, therefore, he must hold that even such a Moser may be killed.

Pri ha'Aretz (13, cited in R. Akiva Eiger): Edus b'Yehosef (34) says that the Rif permits destroying a Moser's money after he was Moser, for then we cannot kill him and (he himself will use his money, so) we need not leave his money for a righteous heir. If so, how did the Rif learn from 62a? All agree afterwards! Rather, the Rif does not distinguish between before and after.

SMA (29): A Moser is like a Rodef, but he is no worse than a Rodef. After he was Moser, he cannot be killed without warning and Beis Din, unless he is established to be Moser.