Sahih Bukhari Volume 009, Book 083, Hadith Number 047.

Narrated By Abu Huraira : Allah's Apostle said, "There is no Diya for persons killed by animals or for the one who has been killed accidentally by falling into a well or for the one killed in a mine. And one-fifth of Rikaz (treasures buried before the Islamic era) is to be given to the state."

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