Al-Kāfi - Volume 7 > Inheritance of People Killed, those who Inherit and those who do not Inherit from the Wergild
Hadith #7

7- مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ عَلِيِّ بْنِ النُّعْمَانِ عَنْ يَحْيَى الأزْرَقِ قَالَ سَأَلْتُ أَبَا عَبْدِ اللهِ (عَلَيْهِ السَّلام) عَنِ الرَّجُلِ يُقْتَلُ وَيَتْرُكُ دَيْناً وَلَيْسَ لَهُ مَالٌ فَيَأْخُذُ أَوْلِيَاؤُهُ الدِّيَةَ أَعَلَيْهِمْ أَنْ يَقْضُوا دَيْنَهُ قَالَ نَعَمْ قُلْتُ وَإِنْ لَمْ يَتْرُكْ شَيْئاً قَالَ نَعَمْ إِنَّمَا أَخَذُوا دِيَتَهُ فَعَلَيْهِمْ أَنْ يَقْضُوا دَيْنَهُ.

7. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from Ali ibn al-Nu’man from Yahya al-Arzaq who has narrated the following: “I once asked abu ‘ Abd Allah, ‘Alayhi al-Salam, about the case of a man who is killed, leaving behind a debt and has left no assets but his heirs receive the wergild; if they must pay his debt. He (the Imam) said, ‘Yes, they must do so.’ I then asked, ‘Even if he does not leave anything they must pay his debts?’ He (the Imam) said, ‘Yes, because they have received the wergild, thus, they must pay his debt.’”