Muwatta Imam Malik Book of Fara'id, Hadith 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."

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ رَبِيعَةَ بْنِ أَبِي عَبْدِ الرَّحْمَنِ، عَنْ غَيْرِ، وَاحِدٍ، مِنْ عُلَمَائِهِمْ . أَنَّهُ لَمْ يَتَوَارَثْ مَنْ قُتِلَ يَوْمَ الْجَمَلِ وَيَوْمَ صِفِّينَ وَيَوْمَ الْحَرَّةِ ثُمَّ كَانَ يَوْمَ قُدَيْدٍ فَلَمْ يُوَرَّثْ أَحَدٌ مِنْهُمْ مِنْ صَاحِبِهِ شَيْئًا إِلاَّ مَنْ عُلِمَ أَنَّهُ قُتِلَ قَبْلَ صَاحِبِهِ . قَالَ مَالِكٌ وَذَلِكَ الأَمْرُ الَّذِي لاَ اخْتِلاَفَ فِيهِ وَلاَ شَكَّ عِنْدَ أَحَدٍ مِنْ أَهْلِ الْعِلْمِ بِبَلَدِنَا وَكَذَلِكَ الْعَمَلُ فِي كُلِّ مُتَوَارِثَيْنِ هَلَكَا بِغَرَقٍ أَوْ قَتْلٍ أَوْ غَيْرِ ذَلِكَ مِنَ الْمَوْتِ إِذَا لَمْ يُعْلَمْ أَيُّهُمَا مَاتَ قَبْلَ صَاحِبِهِ لَمْ يَرِثْ أَحَدٌ مِنْهُمَا مِنْ صَاحِبِهِ شَيْئًا وَكَانَ مِيرَاثُهُمَا لِمَنْ بَقِيَ مِنْ وَرَثَتِهِمَا يَرِثُ كُلَّ وَاحِدٍ مِنْهُمَا وَرَثَتُهُ مِنَ الأَحْيَاءِ . وَقَالَ مَالِكٌ لاَ يَنْبَغِي أَنْ يَرِثَ أَحَدٌ أَحَدًا بِالشَّكِّ وَلاَ يَرِثُ أَحَدٌ أَحَدًا إِلاَّ بِالْيَقِينِ مِنَ الْعِلْمِ وَالشُّهَدَاءِ وَذَلِكَ أَنَّ الرَّجُلَ يَهْلِكُ هُوَ وَمَوْلاَهُ الَّذِي أَعْتَقَهُ أَبُوهُ فَيَقُولُ بَنُو الرَّجُلِ الْعَرَبِيِّ قَدْ وَرِثَهُ أَبُونَا فَلَيْسَ ذَلِكَ لَهُمْ أَنْ يَرِثُوهُ بِغَيْرِ عِلْمٍ وَلاَ شَهَادَةٍ إِنَّهُ مَاتَ قَبْلَهُ وَإِنَّمَا يَرِثُهُ أَوْلَى النَّاسِ بِهِ مِنَ الأَحْيَاءِ . قَالَ مَالِكٌ وَمِنْ ذَلِكَ أَيْضًا الأَخَوَانِ لِلأَبِ وَالأُمِّ يَمُوتَانِ وَلأَحَدِهِمَا وَلَدٌ وَالآخَرُ لاَ وَلَدَ لَهُ وَلَهُمَا أَخٌ لأَبِيهِمَا فَلاَ يُعْلَمُ أَيُّهُمَا مَاتَ قَبْلَ صَاحِبِهِ فَمِيرَاثُ الَّذِي لاَ وَلَدَ لَهُ لأَخِيهِ لأَبِيهِ وَلَيْسَ لِبَنِي أَخِيهِ لأَبِيهِ وَأُمِّهِ شَىْءٌ . قَالَ مَالِكٌ وَمِنْ ذَلِكَ أَيْضًا أَنْ تَهْلَكَ الْعَمَّةُ وَابْنُ أَخِيهَا أَوِ ابْنَةُ الأَخِ وَعَمُّهَا فَلاَ يُعْلَمُ أَيُّهُمَا مَاتَ قَبْلُ فَإِنْ لَمْ يُعْلَمْ أَيُّهُمَا مَاتَ قَبْلُ لَمْ يَرِثِ الْعَمُّ مِنِ ابْنَةِ أَخِيهِ شَيْئًا وَلاَ يَرِثُ ابْنُ الأَخِ مِنْ عَمَّتِهِ شَيْئًا .