a Muslim and a disbeliever participate in killing a disbeliever. It is known that a Muslim is not executed in retaliation for a disbeliever; thus, the disbeliever is to be executed, while the Muslim is liable for half the blood-money.
Similarly, if a slave and a free person participate in killing a slave, the free person is not executed in retaliation for the slave, whereas the slave is executed for him. In this case, then, the slave is executed and the free person is not, but the latter is liable for half of his blood-money—that is, half of his value.
Likewise, if one person acts intentionally and another accidentally in killing someone, the intentional killer is subject to execution, while the one who acted accidentally is liable for half the blood-money. For example, one man deliberately kills a person, while another shoots at game but strikes that person; and the person dies as a result of both acts. Here, the intentional killer is executed, whereas the one who acted accidentally is not. This is the position followed by the author.
According to the authoritative position of the school, however, if an intentional killer and one who acted accidentally participate in a killing, neither is subject to legal retaliation. This is because the act of one of them—the accidental act—is not such as warrants legal retaliation, and we do not know whether the victim died from the accidental act or the intentional one. Therefore, the ruling of legal retaliation is set aside. But if an unrelated person and a father participate in killing the father's child, the act is one that warrants legal retaliation, while execution is precluded in the father’s case due to a factor particular to him—namely, fatherhood. Hence, we execute the unrelated person in retaliation, but not the father.
The author, may Allah have mercy on him, did not distinguish between the two cases. The correct view is that, because in both cases the killing cannot be specifically attributed to the one against whom legal retaliation would apply, legal retaliation is waived.
This issue has three views:
The first is that the ruling is apportioned: legal retaliation is due from the accomplice in whose case the conditions for legal retaliation are fulfilled, but not from the one in whose case they are not fulfilled. This is the position followed by the author.