Musannaf Ibn Abi Shayba 18:467

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Isma’il ibn Abi Khalid, from Tariq, from al-Sha’bi regarding a slave who killed a man, and it reached his master, so he emancipated him. He said: His emancipation is valid, and the blood money (diya) is upon his master.