Sahih Al Bukhari Hadith Number 1346

Narrated Jabir: The Prophet (peace be upon him) said, “Bury them (i.e. martyrs) with their blood.” (that was) On the day of the Battle of Uhud. He did not get them washed

23  Funerals (Al-Janaa’iz)
Hadith number 1346
Volume no 2
Chapter: 74 (Whoever thinks no bath is required for the martyrs)