Answer
✅Answer: Unlawful wealth that is mixed with lawful wealth is of two types: one is the unlawful wealth that is distinguishable and its owners are known to the person, and the second is the unlawful wealth whose owners and amount are unknown.
✅In the case where the owner of the unlawful wealth is known, please pay attention to the following narrations:
قَالَ أَبُو عَبْدِ اللَّهِ مَنْ أَکَلَ مِنْ مَالِ أَخِیهِ ظُلْماً وَ لَمْ یَرُدَّهُ عَلَیْهِ أَکَلَ جَذْوَةً مِنَ النَّارِ یَوْمَ الْقِیَامَةِ
📚 Thawab al-A'mal, p. 243
Translation: Imam al-Sadiq (peace be upon him) said: The one who unjustly eats his brother's wealth and does not return it to him will eat a piece of fire on the Day of Judgment.
شَیْخٍ مِنَ النَّخَعِ قَالَ: قُلْتُ لِأَبِی جَعْفَرٍ إِنِّی لَمْ أَزَلْ وَالِیاً مُنْذُ زَمَنِ الْحَجَّاجِ إِلَی یَوْمِی هَذَا فَهَلْ لِی مِنْ تَوْبَةٍ قَالَ فَسَکَتَ ثُمَّ أَعَدْتُ عَلَیْهِ فَقَالَ لَا حَتَّی تُؤَدِّیَ إِلَی کُلِّ ذِی حَقٍّ حَقَّهُ
📚 Al-Kafi, vol. 2, p. 331
A sheikh from the Nakha' tribe says: I said to Imam al-Baqir (peace be upon him): I have been a governor since the time of Hajjaj until today. Is there any repentance for me? The Imam was silent, and I repeated the matter to him. The Imam said: No, unless you give the right of every rightful owner back to him.
أَبُو جَعْفَرٍ قَالَ رَسُولُ اللَّهِ مَنِ اقْتَطَعَ مَالَ مُؤْمِنٍ غَصْباً بِغَیْرِ حَقِّهِ لَمْ یَزَلِ اللَّهُ مُعْرِضاً عَنْهُ مَاقِتاً لِأَعْمَالِهِ الَّتِی یَعْمَلُهَا مِنَ الْبِرِّ وَ الْخَیْرِ لَا یُثْبِتُهَا فِی حَسَنَاتِهِ حَتَّی یَتُوبَ وَ یَرُدَّ الْمَالَ الَّذِی أَخَذَهُ إِلَی صَاحِبِهِ
📚 Thawab al-A'mal, p. 273
The Messenger of God (peace of God be upon him and his family) said: The one who usurps and takes a believer's wealth unjustly, God will always turn away from him and be angry at the good deeds he performs, and He will not record them in his good deeds until he repents and returns the wealth he took to its owner.
سَمَاعَةَ عَنْ أَبِی عَبْدِ اللَّهِ أَوْ أَبِی الْحَسَنِ قَالَ سَأَلْتُهُ عَنْ رَجُلٍ أَکَلَ مِنْ مَالِ الْیَتِیمِ هَلْ لَهُ تَوْبَةٌ قَالَ یَرُدُّ إِلَی أَهْلِهِ
📚 Tafsir al-Ayyashi, vol. 1, p. 224
Sam'ah says: I asked Imam al-Sadiq or Imam al-Kazim (peace be upon them): A man has eaten from an orphan's wealth. Is there any repentance for him? The Imam said: He should return (that wealth) to its people and owner.
✅There are many narrations on the obligation of returning unlawful wealth to its owner, a few of which were mentioned. However, if lawful and unlawful wealth are mixed and cannot be distinguished, and the owners are also unknown, we act upon the following narrations:
أَبِی عَبْدِ اللَّهِ قَالَ إِنَّ رَجُلًا أَتَی أَمِیرَ الْمُؤْمِنِینَ فَقَالَ یَا أَمِیرَ الْمُؤْمِنِینَ إِنِّی أَصَبْتُ مالاً لَا أَعْرِفُ حَلَالَهُ مِنْ حَرَامِهِ فَقَالَ لَهُ أَخْرِجِ الْخُمُسَ مِنْ ذَلِکَ الْمَالِ فَإِنَّ اللَّهَ عَزَّ وَ جَلَّ قَدْ رَضِیَ مِنْ الْمَالِ بِالْخُمُسِ وَ اجْتَنِبْ مَا کَانَ صَاحِبُهُ یُعْلَمُ
📚 Tahdhib, vol. 4, p. 124
Imam al-Sadiq (peace be upon him) said: A man came to the Commander of the Faithful and said: O Commander of the Faithful, I have acquired wealth whose lawful part I do not distinguish from its unlawful part. The Imam said to him: Take out one-fifth of that wealth, for God Almighty has been pleased with one-fifth of the wealth, and avoid (return to its owner) the wealth whose owner is known.
أَبِی عَبْدِ اللَّهِ قَالَ أَتَی رَجُلٌ أَمِیرَ الْمُؤْمِنِینَ فَقَالَ إِنِّی کَسَبْتُ مَالًا أَغْمَضْتُ فِی مَطَالِبِهِ حَلَالًا وَ حَرَاماً وَ قَدْ أَرَدْتُ التَّوْبَةَ وَ لَا أَدْرِی الْحَلَالَ مِنْهُ وَ الْحَرَامَ وَ قَدِ اخْتَلَطَ عَلَیَّ فَقَالَ أَمِیرُ الْمُؤْمِنِینَ تَصَدَّقْ بِخُمُسِ مَالِکَ فَإِنَّ اللَّهَ رَضِیَ مِنَ الْأَشْیَاءِ بِالْخُمُسِ وَ سَائِرُ الْمَالِ لَکَ حَلَالٌ
📚 Al-Kafi, vol. 5, p. 125
Imam al-Sadiq (peace be upon him) said: A man came to the Commander of the Faithful and said: I have acquired wealth in a way that I was heedless of its lawful and unlawful parts, and I intend to repent, but I cannot distinguish its unlawful part from its lawful part, and the matter has become mixed up and confused for me. The Commander of the Faithful (peace be upon him) said: Give one-fifth of that wealth as charity, for God has been pleased with one-fifth in matters, and the rest of the wealth is lawful for you.
✅Imam al-Sadiq (peace be upon him) said: One-fifth is obligatory on what is extracted from mines and the sea, on spoils and lawful wealth mixed with unlawful wealth in which the owner is unknown, and on treasures.
📚 Al-Khisal, vol. 1, p. 290
✅According to the above narrations, if lawful and unlawful wealth are mixed in a way that they cannot be distinguished and their owners are also unknown, one-fifth of that wealth, which is one-fifth of it, is given to the owners of the khums (one-fifth), who are now available, meaning orphaned, poor, and stranded Sayyids, and the rest of the wealth can be used.