Killing a Muslim in Retaliation for a Disbeliever

Question:
He says: Honorable Shaykh, may Allah grant you success, is it that a Muslim is never killed by a disbeliever under any circumstances? Or are there cases where a Muslim is killed by a disbeliever?

Answer:
A Muslim is not killed by a disbeliever. It is the Sunnah that a Muslim is not killed by a disbeliever, because one of the conditions for retaliation (qisas) is equivalence between the victim and the killer, and a disbeliever is not the equivalent of a Muslim. Therefore, the penalty is the diyah (blood money), and there is no execution. However, if this is in the context of spreading corruption on earth, such as cutting off the road, then the one who cuts off the road is executed, even if he is among the musta'min (non-Muslims granted safe conduct). Yes.