Narrated Rafi ibn Khadij: A man of the Ansar was killed at Khaybar and his relatives went to the Prophet ﷺ and mentioned that to him. He asked: Have you two witnesses who can testify to the murderer of your friend? They replied: Messenger 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 ﷺ paid the blood-wit himself.
Hadith Referenceسنن ابي داود / كتاب الديات / 4524
Hadith Gradingالألبانی:صحيح لغيره | زبیر علی زئی:صحيح, مشكوة المصابيح (3532), وللحديث شواھد كثيرة جدًا منھا الحديث السابق (4523)
Benefits and Issues: The correct and preferred opinion is that first, fifty people from among the claimants will take oaths to establish their claim; then, oaths and so on will be taken from the opposing party.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 4524