Merits of the Helpers in Madinah (Ansaar)
Bukhari :: Book 5 :: Volume 58 :: Hadith 188
Narrated 'Amr bin Maimun:
During the pre-lslamic period of ignorance I saw a she-monkey surrounded by a number of monkeys. They were all stoning it, because it had committed illegal sexual intercourse. I too, stoned it along with them.