Sahih al-Bukhari 1340
Narrated Ibn `Abbas:
The Prophet (p.b.u.h) offered the funeral prayer of a man one night after he was buried, he and his 
companions stood up (for the Prayer). He had asked them about him before standing, saying, "Who is 
this?" They said, "He is so and so and was buried last night." So all of them offered the funeral prayer.
حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا جَرِيرٌ، عَنِ الشَّيْبَانِيِّ، عَنِ الشَّعْبِيِّ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ صَلَّى النَّبِيُّ صلى الله عليه وسلم عَلَى رَجُلٍ بَعْدَ مَا دُفِنَ بِلَيْلَةٍ قَامَ هُوَ وَأَصْحَابُهُ، وَكَانَ سَأَلَ عَنْهُ فَقَالَ ‏
"‏ مَنْ هَذَا ‏"‏‏.‏ فَقَالُوا فُلاَنٌ، دُفِنَ الْبَارِحَةَ‏.‏ فَصَلَّوْا عَلَيْهِ‏.‏