What is the ruling on a teacher who lightly struck his student on the hand, and the student died; is an expiation (kaffarah) or blood money (diyah) obligatory upon him?

If the teacher disciplines the student in a way that is Islamically permissible without transgression, then there is no blame on him. However, if he exceeds what is allowed in discipline and the boy dies because of the blow, then the teacher must offer expiation (kaffarah), which is freeing a slave. If he cannot find one, then he must fast for two consecutive months. And his aqilah (male relatives on the father's side) must pay the blood money (diyah) to the boy's guardians, because this is considered semi-intentional killing. However, if the blow is not ordinarily expected to cause death, and the boy died due to another cause that coincided with the blow, then the teacher is not liable.