Musannaf Ibn Abi Shayba 19:879

Abu Bakr narrated to us, he said: Sahl ibn Yusuf narrated to us, from ‘Amr, from al-Hasan, regarding the disbeliever: If he commits adultery and the prescribed punishment (hadd) is carried out upon him, then he embraces Islam, and a man accuses him of adultery (qadhf) and says, "I only meant his adultery that occurred while he was in his state of disbelief," he said: The prescribed punishment (hadd) is carried out upon the one who accused him.