Musannaf Ibn Abi Shayba 19:83

Abu Bakr narrated to us, he said: Marwan bin Mu'awiyah narrated to us, from Humayd, from Anas, that a boy was brought to Abu Bakr who had stolen, but his puberty was not evident. So he measured him with a span, and he was short by a fingertip, so he left him and did not cut his hand.