Musannaf Ibn Abi Shayba 19:509

Abu Bakr narrated to us, he said: Isa ibn Yunus narrated to us, from Ibn Awn, he said: Miskin, a man from my family, narrated to me, he said: I witnessed Ali, when a man and a woman were brought to him who were found in a ruin. Ali said to him, "Did you have intercourse with her?" Ali’s companions began saying to him, "Say no." So he said, "No." Then he let him go.