Musannaf Ibn Abi Shayba 19:528

Abu Bakr (Usama) narrated to us, he said: Waki’ narrated to us, from Samurah ibn Abd al-Rahman, who said: I saw in al-Hirah a man whose hand had been severed from the joint. I said, "Who severed your hand?" He said, "The righteous man, Ali, severed it. And he did not wrong me."