CITE Sefer Chofetz Chaim hilchos rechilus chapter 6 end of note 20 in halacha 9 and halacha 10

Note 20: a classic example of when one might have circumstantial evidence, but you can’t take matters into your own hand is in a case where Shimon found out he had money stolen. He and his family went away and left Reuvain to sleep the night. The next morning Shimon came back to his house and found his drawer open and a whole wad of money missing. He might even see a wad of cash sticking out of Reuvain’s bag and even confront Reuvain and he said he did not here any burglars break in last night. However, Shimon can’t just grab the money away. He can only take Reuvain to court to force him to swear a rabbinic oath that he didn’t steal Shimon’s money. This is the apparent view of the Shach and Taz in Choshen Mishpat 75, Shach (4) sand Taz (17), though the Sm’a (49) argues. Whether you can verbally degrade the suspect because you have circumstantial evidence that the rechilus is true the Chofetz Chaim is unsure about and leaves it tzarich iyun gadol.

Halacha 10: There is a very serious problem that we find even now a days where one business (or political campaign) might have been hurt because of a smear campaign by another business (or his political opponent), both owned by Jews (or are Jewish), and there is circumstantial evidence that points to the Jewish owner of the competitor personally involve in the smear campaign, the first owner who lost a lot of business and money might think, if he can smear me I can smear him back. But that is absolutely wrong for a number of reasons.

  1. One is only allowed to smear his competitor or opponent if by doing so it will be of positive use in the future, for example to stop any further damage, and there is no other way to save oneself. But one may not do it out if revenge. (See Choshen Mishpat 388:9 in the Rem”a.)

One is only allowed to smear his competitor or opponent in order to stop him from doing further damage only if you heard it from his own mouth, but if you just have circumstantial evidence even if it seems pretty obvious like a commercial put out smearing his competitor or opponent, as long as you don’t know for sure, like if it was clarified in court, or even outside of court you found out that it was definitely him that put out the commercial, for example, and not supporters of him, or people that work under him without his knowledge or approbation, then you cannot go after him. You would have to go after the perpetrators themselves to stop things from escalating. Certainly if you only heard secondhand knowledge that your competitor or opponent is smearing you then you can’t use against him, and all the more so to cause him a loss, even on a miniscule level and even if you think his loss will minimize your loss in the future, it is still forbidden.