Musnad Ahmad Hadith 9266

It is narrated from Abu Huraira (may Allah be pleased with him) that I heard the Messenger (peace and blessings of Allah be upon him) say: The blood of one who dies from an animal's wound is wasted; the blood of one who dies by falling into a well is wasted; the blood of one who dies in a mine is also wasted. And for the buried treasure (rikaz) that someone finds, one-fifth (khums) is obligatory. Whoever buys a goat (and is deceived) whose udders have been tied, he has the choice of two things: either he keeps the animal with himself (and settles the matter), or he returns the animal to the owner and gives along with it one sa’ of dates.