Musannaf Ibn Abi Shayba 18:1138

Abu Bakr narrated to us, he said: Ghundar narrated to us, from Hisham al-Dastawa'i, from Yahya ibn Abi Kathir, that Ali and Marwan used to say: "The blood money (diyah) for the free portion of him is paid according to what he performed, and whatever of him is enslaved, its blood money is the blood money of a slave."