Musannaf Ibn Abi Shayba 18:1152

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Abu Malik narrated to us, from Ali ibn al-Aqmar: That a man hired three men to dig a wall for him, so they all struck at its base together, and it fell upon them. One of them died, and they disputed before Shurayh. He judged against the remaining two for two-thirds of the blood money.