Musnad Ahmad 5:622

Abdullah narrated to us, Muhammad ibn Abi Bakr al-Muqaddami narrated to us, Hammad ibn Zayd narrated to us, Jamil ibn Murrah narrated to us, from Abu al-Wadi’, who said: I witnessed Ali when he killed the people of al-Nahrawan. He said: "Search among the slain." They said: "We did not find him." He said: "Search for him, for by Allah, I have not lied, nor have I been lied to." Until they extracted him from beneath the slain. Abu al-Wadi’ said: It is as if I am looking at him; he was an Abyssinian, one of his hands was like a woman’s breast, upon it were hairs like the tail of a jerboa.