Musannaf Ibn Abi Shayba 19:695

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Hisham ibn Sa’d, he said: Yazid ibn Nu’aym ibn Hazzal narrated to me, from his father, he said: Ma’iz ibn Malik was under the care of my father, and he had relations with a slave girl from the tribe. My father said to him: "Go to the Messenger of Allah (may Allah bless him and grant him peace) and inform him of what you have done, so that he may seek forgiveness for you." He only intended by that to provide him with a way out. So he went to him and said: "O Messenger of Allah, I have committed adultery, so establish the Book of Allah upon me." He turned away from him. Then he came to him until he had mentioned it four times. Then he came to him the fourth time and said: "O Messenger of Allah, I have committed adultery, so establish the Book of Allah upon me." The Messenger of Allah (may Allah bless him and grant him peace) said: "Did you not say it four times?" He asked: "With whom?" He said: "With so-and-so." He asked: "Did you lie beside her?" He said: "Yes." He asked: "Did you touch her?" He said: "Yes." He asked: "Did you have intercourse with her?" He said: "Yes." He said: "So he ordered that he be stoned." He was taken out to the rocky tract (al-harrah). When he felt the touch of the stones, he ran away. Abdullah ibn Unays met him, and he had outrun his companions, so he pulled out a camel’s shank bone and threw it at him, killing him. Then he came to the Prophet (may Allah bless him and grant him peace) and mentioned that to him. He said: "Why did you not leave him? Perhaps he would have repented, and Allah would have accepted his repentance."