The Torah establishes in Parashat Mishpatim (Shemot 21:28) that an ox that fatally gored a human being is sentenced to death by stoning, and the verse adds, “Ve’lo Ye’achel Et Besaro” – “its flesh shall not be eaten.” This means that a “Shor Ha’niskal” – an ox sentenced to stoning for having killed a person – is forbidden for any sort of benefit. Even if somebody came along and properly slaughtered the ox, following all the detailed guidelines of Shehita (halachic slaughtering), the meat is forbidden for consumption. Likewise, all other parts of the animal – the hair, the horns, the bones, the hide, the blood and the sinews – may not be used for any purpose.
This applies not only to an ox, but to any animal that kills a human being. Once Bet Din rules that the animal must be put to death, the animal becomes forbidden for any sort of benefit. If the animal is a female mammal, its milk, too, is forbidden, by force of the halachic principle of “Ha’yoseh Min Ha’tameh Tameh” – something which emerges from the body of a forbidden creature is itself forbidden. By the same token, if a bird is sentenced to death for killing a person, its eggs are forbidden.
This prohibition applies to both men and women. One who transgresses this prohibition and eats the meat of such an animal is liable to Malkut.
The reason behind this command, the Sefer Ha’hinuch explains, is to show us the severity of inflicting harm on people. The Torah went so far as to forbid benefit from an animal which killed somebody, even though the animal, quite obviously, cannot be held personally accountable for its actions, to show us that even accidentally causing people harm is something repugnant. Seeing how the Torah treats a “Shor Ha’niskal,” we will be motivated to exercise care to ensure that we do not cause any sort of damage or harm to anybody, even accidentally.
Although the animal becomes forbidden only once Bet Din sentences it to stoning, and not any earlier, nevertheless, the animal may not be slaughtered after it killed somebody. In order to give Bet Din a chance to sentence the animal, Halacha forbids slaughtering it even before the sentencing. This Halacha gives rise to the question of whether an animal that kills a person may be slaughtered and eaten nowadays, a question raised and discussed by the Bah (Rav Yoel Sirkis, Poland, 1561-1640). Nowadays, when courts do not have the authority to sentence offenders to capital punishment, they also lack the authority to sentence animals to execution. We might assume, then, that the prohibition against benefiting from a “Shor Ha’niskal” has no practical relevance nowadays, and an animal that kills somebody may be slaughtered and eaten. This is, in fact, the view of several Poskim. Some even specifically recommend slaughtering the animal because it poses a threat.
Others, however, maintain that even nowadays, one should not slaughter an animal that had killed somebody, because each day, we anticipate the rebuilding of the Bet Ha’mikdash and the restoration of the full authority of Bet Din. Although now courts do not have the authority to execute an animal that killed somebody, we hope every day for the arrival of Mashiah, at which point Bet Din will indeed have this authority. Therefore, according to this opinion, an animal that killed should not be slaughtered, and we should instead wait and hope that Bet Din can conduct a proper trial.