Musannaf Ibn Abi Shaybah

Hazrat Shaibani states that Hazrat Sha'bi said: In the region of Wadi'ah in Yemen, a man was found dead. This matter was presented before Hazrat Umar, so he made fifty men among them swear an oath as follows: "We did not kill (him), nor do we know the killer." Then he paid the blood money (diyah) for the murdered man.