Musannaf Ibn Abi Shayba 18:1175

Abu Bakr narrated to us, he said: Hafs narrated to us, from Ash'ath, from al-Hasan, that a man sought water from the people of a tribe, but they refused to give him water. Thirst overtook him, and he died. So, Umar held them liable for the blood money (diyah).