Musannaf Ibn Abi Shaybah 35668 — A man who enters under safe conduct

It is narrated from Yusuf bin Ya'qub that a polytheist killed a Muslim, and then he came under a grant of security, and the brother of the slain man killed him. Umar bin Abd al-Aziz gave a ruling of blood money against him, made it payable from his own wealth, had him imprisoned, and sent the blood money to the slain man's heirs in the abode of war.