Musannaf Ibn Abi Shayba 36:563

Ali ibn Mushir narrated to us, from al-Ajalh, from al-Sha'bi, who said: Abd al-Rahman ibn Muljam and Shabib al-Ashja'i flanked Ali when he went out for the dawn prayer. As for Shabib, he struck him but missed, and his sword stuck in the wall. He was then cornered toward the doors of Kindah, and the people said, "Seize the owner of the sword." When he feared he would be captured, he threw away the sword and entered among the people. As for Abd al-Rahman, he struck him with the sword on the crown of his head. He was then cornered toward the Gate of the Elephant (Bab al-Fil). 'Urayd or 'Uwayd al-Hadrami caught up with him and seized him, then brought him in to Ali. Ali said, "If I die, then kill him. And if you wish, pardon him. And if I survive, then it is [a matter of] legal retaliation (qisas)."