Yahya related to me from Malik that he heard that Umar ibn Abd al-Aziz gave a decision that when a jew or christian was killed, his blood-money was half the blood-money of a free muslim.

Malik said, "What is done in our community, is that a muslim is not killed for a kafir unless the muslim kills him by deceit. Then he is killed for it."

Muwatta Malik Book 43, Hadith 29