Musannaf Ibn Abi Shayba 19:768

Abu Bakr narrated to us, he said: Isma'il bin Ibrahim narrated to us, from Muhammad bin Ishaq, from Muhammad bin Ibrahim, from 'Ata' bin Yasar, that Ma'iz bin Malik came to the Prophet, may Allah bless him and grant him peace, and confessed to himself of adultery. He said: "And with whom?" He said: "With so-and-so, the freedwoman of the son of so-and-so." So he sent for her, and she denied it, so he let her go and took him for what he had confessed against himself. And he did not mention that he flogged him with the punishment for slander regarding her.