Musannaf Ibn Abi Shayba 37:546

Abu Bakr narrated to us, he said: Ibn ‘Ulayyah narrated to us, from Ibn ‘Awn, from al-Hasan, he said: Wathab informed me—and he was among those who attained the manumission of the Commander of the Faithful, ‘Umar, and he used to be in the presence of ‘Uthman—he said: I saw on his (Wathab’s) hip two stab wounds, as if they were cauterization marks; he was stabbed with them on the day of the House, the house of ‘Uthman. He said: The Commander of the Faithful, ‘Uthman, sent me and said: "Call al-Ashtar." So he came. Ibn ‘Awn said: I think he said: "So I threw a cushion for the Commander of the Faithful." He (Uthman) said: "O Ashtar, what do the people want from me?" He said: "Three things, there is no escape from one of them. They give you the choice between you stripping the command from them, so you say: 'This is your command, so choose for it whom you wish,' or that you allow retaliation against yourself. If you refuse these two, then the people will kill you." He (Uthman) said: "Is there no escape from one of them?" He said: "There is no escape from one of them." He said: "As for stripping the command from them, I would never strip off a garment that Allah has clothed me with. And as for allowing retaliation against myself, by Allah, I know that my two companions (the Prophet and Abu Bakr) before me used to allow retaliation against themselves, but my body cannot endure retaliation. And as for them killing me, by Allah, if they kill me, they will never love one another after me, and they will never fight a common enemy together after me." Ibn ‘Awn said: And someone other than al-Hasan said: "That I be brought forward and my neck be struck is more beloved to me than that I should strip the nation of Muhammad, some of them against others." Ibn ‘Awn said: And this is more similar to his speech. Al-Ashtar stood up and left. We waited and said: "Perhaps the people (will desist)." Then a small man came, as if he were a wolf, and he peered through the door, then returned. Then Muhammad ibn Abi Bakr came with thirteen men until he reached ‘Uthman. He grabbed his beard and pulled it until I heard his teeth clatter. He said: "What did Mu’awiyah avail you? What did Ibn ‘Amir avail you? What did your letters avail you?" He (Uthman) said: "Release my beard, O son of my brother. Release my beard, O son of my brother." He said: Then I saw him call for help against a man from the group by name, so he stood up to him with a broad-headed arrow and struck him in his head, and he incapacitated him. Then he passed by. He said: Then they entered upon him, by Allah, until they killed him.