Musannaf Ibn Abi Shayba 18:857

Abu Bakr narrated to us, he said: Muhammad ibn Bishr narrated to us, he said: Abd al-Aziz narrated to me regarding a man whose masters (mawali) said: "We will not pay the blood money (diya) on his behalf." So he wrote to the judge to compel them to pay the blood money, for I have no doubt that they were the ones who would inherit from him.