Types of Blood-Wit (Kitab Al-Diyat)
Dawud :: Book 39 : Hadith 4509
Narrated Rafi' ibn Khadij:
A man of the Ansar was killed at Khaybar and his relatives went to the Prophet (peace_be_upon_him) and mentioned that to him. He asked: Have you two witnesses who can testify to the murderer of your friend? They replied: Apostle of Allah! there was not a single Muslim present, but only Jews who sometimes have the audacity to do even greater crimes than this. He said: Then choose fifty of them and demand that they take an oath; but they refused and the Prophet (peace_be_upon_him) paid the blood-wit himself.