Maliks Muwatta Book 27, Hadith Number 13.
Section : Inheritance from People of Other Religions.
Yahya related to me from Malik from Yahya ibn Said from Ismail ibn Abi Hakim that Umar ibn Abd al-Aziz freed a christian who then died. Ismail said, “Umar ibn Abd al-Aziz ordered me to put his property in the bayt al-mal.”