✅ Answer: Refer to the following narrations:

1 عَنْ هِشَامِ بْنِ سَالِمٍ عَنْ أَبِي عَبْدِ اللَّه قَالَ: قَالَ رَسُولُ اللَّه لَا مِيرَاثَ لِلْقَاتِلِ.

📚 al-Kāfī, vol. 7, p. 141

Imam al-Sadiq (peace be upon him) said: The Messenger of Allah (peace be upon him and his family) said: The killer has no inheritance!

2 عَنْ أَبِي بَصِيرٍ عَنْ أَبِي عَبْدِ اللَّه قَالَ: لَا يَتَوَارَثُ رَجُلَانِ قَتَلَ أَحَدُهُمَا صَاحِبَهُ.

📚 al-Kāfī, vol. 7, p. 140

Imam al-Sadiq (peace be upon him) said: Two people, one of whom kills the other, do not inherit from each other!

3 عَنْ عَبْدِ اللَّهِ بْنِ أَبِي يَعْفُورٍ قَالَ: قُلْتُ لِأَبِي عَبْدِ اللَّهِ هَلْ لِلْمَرْأَةِ مِنْ دِيَةِ زَوْجِهَا وَ هَلْ لِلرَّجُلِ مِنْ دِيَةِ امْرَأَتِهِ شَيْءٌ قَالَ نَعَمْ مَا لَمْ يَقْتُلْ أَحَدُهُمَا الْآخَرَ.

📚 al-Kāfī, vol. 7, p. 141

ʿAbdullah ibn Abi Yaʿfur said: I asked Imam al-Sadiq (peace be upon him): Does a woman inherit anything from the blood money of her husband? And does a man inherit anything from the blood money of his wife? He replied: Yes, as long as one of them has not killed the other (intentionally)!

4 عَنْ سُلَيْمَانَ بْنِ خَالِدٍ عَنْ أَبِي عَبْدِ اللَّه قَالَ: قَضَى عَلِيٌّ فِي دِيَةِ الْمَقْتُولِ أَنَّهُ يَرِثُهَا الْوَرَثَةُ عَلَى كِتَابِ اللَّهِ وَ سِهَامِهِمْ إِذَا لَمْ يَكُنْ عَلَى الْمَقْتُولِ دَيْنٌ إِلَّا الْإِخْوَةَ وَ الْأَخَوَاتِ مِنَ الْأُمِّ فَإِنَّهُمْ لَا يَرِثُونَ مِنْ دِيَتِهِ شَيْئاً.

📚 al-Kāfī, vol. 7, p. 139

Imam al-Sadiq (peace be upon him) said: Amir al-Mu’minin (peace be upon him) ruled regarding the diyya of a murdered person that the heirs inherit it according to the Qur’an and their shares, provided the deceased has no debts — except maternal brothers and sisters, who do not inherit from the diyya!

5 عَنْ إِسْحَاقَ بْنِ عَمَّارٍ عَنْ جَعْفَرٍ أَنَّ رَسُولَ اللَّهِ قَالَ: إِذَا قُبِلَتْ دِيَةُ الْعَمْدِ فَصَارَتْ مَالًا فَهِيَ مِيرَاثٌ كَسَائِرِ الْأَمْوَالِ.

📚 al-Tahdhīb, vol. 9, p. 377

The Messenger of Allah (peace be upon him and his family) said: If intentional killing is pardoned and the compensation is accepted as money, then it is like other wealth and is part of the inheritance!

6 عَنْ حَفْصِ بْنِ غِيَاثٍ قَالَ: سَأَلْتُ جَعْفَرَ بْنَ مُحَمَّدٍ عَنْ طَائِفَتَيْنِ مِنَ الْمُؤْمِنِينَ إِحْدَاهُمَا بَاغِيَةٌ وَ الْأُخْرَى عَادِلَةٌ اقْتَتَلُوا فَقَتَلَ رَجُلٌ مِنْ أَهْلِ الْعِرَاقِ أَبَاهُ أَوِ ابْنَهُ أَوْ أَخَاهُ أَوْ حَمِيمَهُ وَ هُوَ مِنْ أَهْلِ الْبَغْيِ وَ هُوَ وَارِثُهُ أَ يَرِثُهُ قَالَ نَعَمْ لِأَنَّهُ قَتَلَهُ بِحَقٍّ.

📚 al-Fiqh al-Manṣūr (al-Faqīh), vol. 4, p. 319

Hafs said: I asked Imam al-Sadiq (peace be upon him) about two groups of believers, one aggressor and the other just, who fight each other, and someone from Iraq kills his father, son, brother, or relative who was among the aggressors — and he is his heir. Does he inherit from him? He replied: Yes, because he killed him rightfully!

7 عَنِ السَّكُونِيِّ عَنْ أَبِي عَبْدِ اللَّهِ قَالَ: قَالَ أَمِيرُ الْمُؤْمِنِينَ مَنْ أَوْصَى بِثُلُثِ ماله ثُمَّ قُتِلَ خَطَأً فَإِنَّ ثُلُثَ دِيَتِهِ دَاخِلٌ فِي وَصِيَّتِهِ.

📚 al-Kāfī, vol. 7, p. 11

Amir al-Mu’minin (peace be upon him) said: If a person makes a will regarding one-third of his property, and then he is mistakenly killed, then one-third of his diyya is also included in the will!

✅ Based on the above narrations and others: The diyya of a murdered person is like the rest of his wealth. It is first used to settle debts, then to fulfill his will (up to one-third), and the remainder is distributed among the heirs according to inheritance laws. However, if the intentional killer is among the heirs, he does not inherit anything from the diyya or other property. If the deceased was killed justly and rightfully by someone who is also his heir, then the killer does inherit.

✅ If there are no heirs from the first class (children, parents, spouse), and inheritance passes to the second class, then maternal brothers and sisters do not inherit from the diyya, though they do inherit from other wealth.

✅ The rulings concerning the diyya of accidental killing are discussed separately in other narrations.