Regarding bestiality, the law reads (Lev. 20:15), "He shall surely be put to death; and you shall slay the beast." Here the particular mode of death is not stated, but can be infered by means of a Gezerah shawah. Since, with reference to the enticer to idolatry, the Bible (Deut. 13:9) employs the term Harag = "to slay" ("Thou shalt surely slay him"), and this is immediately explained by the addition, "Thou shalt stone him with stones, that he die" (Deut. 13:10), it follows that the term "harag" used in reference to the beast likewise means to slay by stoning. And as for the criminal himself, his sentence is the same as that of the beast in connection with which he is mentioned.
- Wilhelm Bacher and Lewis N. Dembitz, Capital Punishment, Jewish Encyclopedia (1901), at http://www.jewishencyclopedia.com/view.jsp?artid=128&letter=C.