Musannaf Ibn Abi Shayba 18:1302

Abu Bakr narrated to us, he said: Ibn Mahdi narrated to us, from Sufyan, from Yusuf ibn Ya'qub, that a man from the polytheists killed a man from the Muslims, then he entered [the Muslim territory] under a guarantee of safety, so his brother killed him. Umar ibn Abd al-Aziz judged against him [the brother] for the blood money (diyah), and he imposed it upon his wealth, and he detained him in prison, and he sent his blood money to his heirs among the people of war (harbiyyin).