Muwatta Malik 997

Yahya related to me from Malik that he had heard the people of knowledge say that martyrs in the way of Allah were not washed, nor were any of them prayed over. They were buried in the garments in which they were slain. Malik said, "That is the sunna for someone who is killed on the battleground…

وَحَدَّثَنِي عَنْ مَالِكٍ أَنَّهُ بَلَغَهُ عَنْ أَهْلِ الْعِلْمِ أَنَّهُمْ كَانُوا يَقُولُونَ الشُّهَدَاءُ فِي سَبِيلِ اللَّهِ لاَ يُغَسَّلُونَ وَلاَ يُصَلَّى عَلَى أَحَدٍ مِنْهُمْ وَإِنَّهُمْ يُدْفَنُونَ فِي الثِّيَابِ…