Musannaf Ibn Abi Shayba 13:581

Abu Bakr narrated to us, he said: Abu Bakr ibn Ayyash narrated to us, from Mutarrif, from Amir, from Ali, regarding a man who bought a slave girl, and she bore him children, then the man established proof that she belonged to him. He said: She is returned to him, and her children are valued against him, and the one who sold her pays the penalty for what he has done.