Musannaf Ibn Abi Shayba 19:259

Abu Bakr narrated to us, he said: Abu Mu’awiyah narrated to us, from al-A’mash, from al-Qasim, from his father, who said: ‘Abdullah was brought a man who was found with a woman under one garment. He said: So he struck them forty [lashes] each. He said: So they went out to ‘Umar to seek justice against him. ‘Umar met ‘Abdullah and said: A people sought justice against you regarding such and such. He informed him of the story. He [‘Umar] said to ‘Abdullah: Is that what you saw? He said: Yes. They said: We came to seek justice against him, and behold, he is asking him for a legal opinion.