Musnad Ahmad 28:448

Al-Fadl ibn Dukayn narrated to us, Sufyan narrated to us, from al-A’mash, from ‘Abd al-Rahman ibn Abi Ziyad, from ‘Abdullah ibn al-Harith, who said: I was walking alongside ‘Abdullah ibn ‘Amr ibn al-‘As and Mu’awiyah. ‘Abdullah ibn ‘Amr said to ‘Amr [ibn al-‘As]: I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: "The transgressing faction will kill him"—meaning ‘Ammar. ‘Amr said to Mu’awiyah: Listen to what this one is saying. So he told him [what he had heard]. He [Mu’awiyah] said: Did we kill him? It was only those who brought him who killed him.