Al-Kāfi - Volume 3 > People Consumed By Beasts, Birds, Pieces of Bodies of Those Killed or Burnt
Hadith #2

2ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنْ أَحْمَدَ بْنِ مُحَمَّدِ بْنِ أَبِي نَصْرٍ عَنْ جَمِيلِ بْنِ دَرَّاجٍ عَنْ مُحَمَّدِ بْنِ مُسْلِمٍ عَنْ أَبِي جَعْفَرٍ (عَلَيْهِ الْسَّلام) قَالَ إِذَا قُتِلَ قَتِيلٌ فَلَمْ يُوجَدْ إِلاَّ لَحْمٌ بِلاَ عَظْمٍ لَهُ لَمْ يُصَلَّ عَلَيْهِ وَإِنْ وُجِدَ عَظْمٌ بِلاَ لَحْمٍ صُلِّيَ عَلَيْهِ. قَالَ وَرُوِيَ أَنَّهُ لاَ يُصَلَّى عَلَى الرَّأْسِ إِذَا أُفْرِدَ مِنَ الْجَسَدِ.

2. Ali ibn Ibrahim has narrated from his father from Ahmad ibn Muhammad ibn abu Nasr from Jamil ibn Darraj from Muhammad ibn Muslim who has said the following: “Abu Ja‘far, ‘Alayhi al-Salam, has said, ‘If one is killed and only flesh without bones are found, Salah (prayer) is not obligatory for it. If bones without flesh are found, there is Salah (prayer) for it.’” He (the narrator) has said, ‘It is narrated that Salah (prayer) is not obligatory for a head found without the body.’”