Musannaf Ibn Abi Shayba 13:582

Abu Bakr narrated to us, he said: Hushaym narrated to us, from Mughira, from Ibrahim, regarding a man who found his slave woman with a man who had purchased her, and she had given birth to a child by him. He said: He takes her, and he takes the value of the child from their father, and he remits a portion of the value for him.