Musannaf Ibn Abi Shaybah 22859 — A mukatab who dies leaving free

It is narrated from Sayyiduna al-Mukhariq (may Allah be pleased with him) that Sayyiduna Ali (may Allah be pleased with him) sent Sayyiduna Muhammad bin Abi Bakr (may Allah be pleased with him) to Egypt. He wrote to him from Egypt asking about a contracted slave (mukatab) who dies leaving wealth and children. He (may Allah be pleased with him) wrote to him concerning the contracted slave: "If he dies leaving enough wealth for the manumission payment, his masters are to be called and the manumission payment is to be paid to them in full, and whatever remains will be an inheritance for his children."