Al-Muwatta Hadith 27.15

Yahya related to me from Malik from Rabia ibn Abi Abd ar-Rahman from more than one of the people of knowledge of that time, that those who were killed on the Day of the Camel, the Day of Siffin, the Day of al-Harra, and the Day of Qudayd did not inherit from each other. None of them inherited anything from his companion unless it was known that he had been killed before his companion. Malik said, "That is the way of doing things about which there is no dispute, and which none of the people of knowledge in our city doubt. The procedure with two mutual heirs who are drowned, or killed in another way, when it is not known which of them died first is the same - neither of them inherits anything from his companion. Their inheritance goes to whoever remains of their heirs. They are inherited from by the living." Malik said, "No one should inherit from anyone else when there is doubt, and one should only inherit from the other when there is certainty of knowledge and witnesses. That is because a man and his mawla whom his father has freed might die at the same time. The sons of the free man could say, 'Our father inherited from the mawla.' They should not inherit from the mawla without knowledge or testimony that he died first. The living people most entitled to his wala' inherit from him." Malik said, "Another example is two full brothers who die. One of them has children and the other does not. They have a half-brother by their father. It is not known which of them died first, so the inheritance of the childless one goes to his half-brother by the father. The children of the full-brother get nothing." Malik said, "Another example is when a paternal aunt and the son of her brother die, or else the daughter of the brother and her paternal uncle. It is not known which of them died first. The paternal uncle does not inherit anything from the daughter of his brother, and the son of the brother does not inherit anything from his paternal aunt."