Musannaf Ibn Abi Shayba 13:3377

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Zakariya narrated to us, from ‘Amir, that he was asked about a man who bought a slave. The buyer said to the seller: "Sell him for me, and he is yours; spend [on him]." Then the slave died in the hands of the seller. He said: The seller is liable for his price.