Al-Kāfi - Volume 3 > About the Souls (spirits) of the Unbelievers
Hadith #3

3ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ مُحَمَّدِ بْنِ أَحْمَدَ بِإِسْنَادٍ لَهُ قَالَ قَالَ أَمِيرُ الْمُؤْمِنِينَ (عَلَيْهِ الْسَّلام) شَرُّ بِئْرٍ فِي النَّارِ بَرَهُوتُ الَّذِي فِيهِ أَرْوَاحُ الْكُفَّارِ.

3. Muhammad ibn Yahya has narrated from Muhammad ibn Ahmad through the chain of his narrators has said the following: “’Amir al-Mu’minin, ‘Alayhi al-Salam, has said, ‘The worst well in the fire is the well of Barahut in which the souls (spirits) of unbelievers live.’”