Sayyiduna Sahl bin Abi Hathmah (may Allah be pleased with him) says: A group of the Ansar went out, and a man among them was killed. The matter was brought before the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Do you have witnesses?" They said: We have no witnesses. He (peace and blessings be upon him) said: "Then shall I take oaths from them (the Jews)?" They said: In that case the Jews would kill us and then swear oaths as well. He (peace and blessings be upon him) said: "Then you yourselves swear the oaths." They said: We were not present at the scene. So the Messenger of Allah (peace and blessings be upon him) paid his blood money.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5607