Musannaf Ibn Abi Shayba 18:1274

Abu Bakr narrated to us, he said: Abu Mu'awiyah narrated to us, from al-A'mash, from Abu Salih, from Abu Hurayrah, who said: A man was killed during the time of the Messenger of Allah, may Allah bless him and grant him peace, and that was raised to the Prophet, may Allah bless him and grant him peace. He handed him over to the guardian of the slain person. The killer said: "O Messenger of Allah, by Allah, I did not intend to kill him." The Prophet, may Allah bless him and grant him peace, said to the guardian: "Know that if he is truthful and you then kill him, you will enter the Fire." He said: So he let him go. He said: And he was bound with a leather strap. He said: So he went out dragging his strap. He said: And he was named "Dhu al-Nusa'" (The Man of the Strap).