Musannaf Ibn Abi Shayba 19:880

Abu Bakr narrated to us, he said: Ma'n ibn 'Isa narrated to us, from Ibn Abi Dhi'b, he said: I asked al-Zuhri about a woman who committed adultery while she was a Jewess, a Christian, or a Magian, then she accepted Islam, and a man accused her of adultery (qadhf). Ibn Shihab said: There is no prescribed punishment (hadd) upon the one who accused her, but he is to be disciplined (yunakkal).