Musnad Abu Ya'la al-Mawsili 117:234

Zuhayr narrated to us, Affan narrated to us, Hammad narrated to us, Qatadah, Humayd, and Thabit informed us, from Anas: That some people from Uraynah came to Medina and found its climate unsuitable. The Messenger of Allah (may Allah bless him and grant him peace) sent them to the camels of the charity and said, "Drink their urine and their milk." They killed the shepherd of the Messenger of Allah (may Allah bless him and grant him peace), drove away the camels, and apostatized from Islam. They were brought to the Prophet (may Allah bless him and grant him peace), so he cut off their hands and feet from opposite sides, gouged out their eyes, and cast them into the Harrah. Anas said: I used to see one of them biting the earth with his mouth until they died. And perhaps Hammad said: Biting the earth with his mouth until they died.