Musannaf Ibn Abi Shayba 18:1142

Abu Bakr narrated to us, he said: Waki’ narrated to us, from Shu’bah, who said: I asked al-Hakam and Hammad about a man who threw fire into the house of some people, and they burned. They said: There is no retaliation (qisas) upon him, and he is not to be killed.