Musannaf Ibn Abi Shayba 38:90

Waki’ narrated to us, from Muhammad ibn Qays, from Sa’d ibn Ibrahim, who said: While Ali was holding the hand of ‘Adi ibn Hatim, and he was walking among the slain, he passed by a man whom I recognized. I said, "O Commander of the Faithful, my last knowledge of this man was that he was a believer." He said, "And now?"