Musannaf Ibn Abi Shayba 19:85

Abu Bakr narrated to us, he said: Muhammad ibn Bakr narrated to us, from Ibn Jurayj, from Ibn Abi Mulaykah, he said: A slave belonging to Umar ibn Abi Rabi'ah who had stolen was brought to Ibn al-Zubayr. He ordered that he be measured, and he was a young boy. He reached six spans, so he cut off his hand.