Musnad Abu Ya'la al-Mawsili 3:215

Ubayd Allah ibn Umar al-Qawariri narrated to us, Yazid ibn Zuray narrated to us, Awf narrated to us, Muhammad ibn Sirin narrated to us, Ubaydah al-Salmani narrated to us, who said: When the people of al-Nahrawan were struck down, Ali said to us: "Search among them, for if they are the people whom the Messenger of Allah (may Allah bless him and grant him peace) mentioned, then among them is a man with a malformed hand (mukhdaj al-yad) or a fleshy-stump hand (muthdan al-yad)." He said: So we searched for him and found him. We called him to him (Ali), and he stood over him and said: "Allah is the Greatest. Were it not that you would become arrogant, I would have told you what Allah has decreed upon the tongue of His Messenger (may Allah bless him and grant him peace) for those who kill these people." He (Ubaydah) said: I said, "Did you hear it from the Messenger of Allah (may Allah bless him and grant him peace)?" He said: "Yes, by the Lord of the Kaaba. Yes, by the Lord of the Kaaba." He said: This reached some of the wives of the Prophet (may Allah bless him and grant him peace), as if she envied him for that. Awf said: I intentionally refrained from mentioning her.