Allah's Messenger (ﷺ) said, "No bloodmoney will be charged if somebody dies in a mine or in a well or is killed by an animal; and if somebody finds a treasure in his land he has to give one-fifth of it to the Government."
Sahih al-Bukhari Book 42, Hadith 5
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Sahih al-Bukhari Book 42, Hadith 4 Next Hadith → The Prophet (ﷺ) said, "Whoever takes a false oath to deprive somebody of his property will meet Allah while He will be angry with him." Allah revealed: 'Verily those who purchase a little gain at the cost of Allah's covenant, and their oaths.' ........(3.77) Al-Ashath came (to the place where `Abdullah was narrating) and said, "What has Abu `Abdur- Rahman (i.e. `Abdullah) been telling you? This verse was revealed concerning me. I had a well in the land of a cousin of mine. The Prophet (ﷺ) asked me to bring witnesses (to confirm my claim). I said, 'I don't have witnesses.' He said, 'Let the defendant take an oath then.' I said, 'O Allah's Messenger (ﷺ)! He will take a (false) oath immediately.' Then the Prophet (ﷺ) mentioned the above narration and Allah revealed the verse to confirm what he had said." (See Hadith No. 692)

Sahih al-Bukhari Book 42, Hadith 6