It was narrated that Sahl bin Abi Hathmah said:

"Abdullah bin Sahl was found slain, and his brother, and two paternal uncles, Huwayysah and Huwayisaah, who were the paternal uncles of 'Abdullah bin Sahl, came to the Messenger of Allah. 'Abdur-Rahman started to speak, but the Messenger of Allah said: "Let the elders speak first." They said: "O Messenger of Allah, we found 'Abdullah bin Sahl slain in one of the dry wells of Khaibar." The prophet said: "Whom do you suspect? They said: "We suspect the Jews." He said: "Will you swear fifty oaths saying that the Jews killed him?" They said: "How can we swear an oath about something that we did not see?" He said: "Then can the Jews swear fifty oaths declaring that they did not kill him?" They said:"How can we accept their oaths, when they are Mushrikun?" So the Messenger of Allah paid the blood money himself.
Malik narrated this in Mursal from.

أَخْبَرَنَا مُحَمَّدُ بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا سُفْيَانُ، قَالَ حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ بُشَيْرِ بْنِ يَسَارٍ، عَنْ سَهْلِ بْنِ أَبِي حَثْمَةَ، قَالَ وُجِدَ عَبْدُ اللَّهِ بْنُ سَهْلٍ قَتِيلاً فَجَاءَ أَخُوهُ وَعَمَّاهُ حُوَيِّصَةُ وَمُحَيِّصَةُ وَهُمَا عَمَّا عَبْدِ اللَّهِ بْنِ سَهْلٍ إِلَى رَسُولِ اللَّهِ ﷺ فَذَهَبَ عَبْدُ الرَّحْمَنِ يَتَكَلَّمُ فَقَالَ رَسُولُ اللَّهِ ﷺ " الْكُبْرَ الْكُبْرَ " . قَالاَ يَا رَسُولَ اللَّهِ إِنَّا وَجَدْنَا عَبْدَ اللَّهِ بْنَ سَهْلٍ قَتِيلاً فِي قَلِيبٍ مِنْ بَعْضِ قُلُبِ خَيْبَرَ . فَقَالَ النَّبِيُّ ﷺ " مَنْ تَتَّهِمُونَ " . قَالُوا نَتَّهِمُ الْيَهُودَ . قَالَ " أَفَتُقْسِمُونَ خَمْسِينَ يَمِينًا أَنَّ الْيَهُودَ قَتَلَتْهُ " . قَالُوا وَكَيْفَ نُقْسِمُ عَلَى مَا لَمْ نَرَ قَالَ " فَتُبَرِّئُكُمُ الْيَهُودُ بِخَمْسِينَ أَنَّهُمْ لَمْ يَقْتُلُوهُ " . قَالُوا وَكَيْفَ نَرْضَى بِأَيْمَانِهِمْ وَهُمْ مُشْرِكُونَ فَوَدَاهُ رَسُولُ اللَّهِ ﷺ مِنْ عِنْدِهِ . أَرْسَلَهُ مَالِكُ بْنُ أَنَسٍ .