Is it permissible to own a treasure trove of money found in a house bought from its deceased owners?

If a treasure is found on a piece of land, one-fifth of it must be given to the zakat recipients, based on the Prophet's (peace be upon him) saying: "And in rikaz (treasure), one-fifth [is due]." As for the remaining four-fifths, scholars have differed on it: 1. The majority (Malikis, Shafi'is, Abu Hanifa, Muhammad, and one narration from Ahmad): They hold that it belongs to the first owner of the land or their heirs if they are known. If they are not known, it should be placed in the Muslim treasury (Bayt al-Mal). 2. Ahmad in one narration, Abu Yusuf, and some Malikis: They believe it belongs to the last owner of the land (the one who finds the treasure) because it is not an integral part of the land but rather something deposited within it. 3. Abu Yusuf, some Malikis, and Abu Thawr: They are of the opinion that it belongs unconditionally to the finder, even if the treasure is found on land not owned by them.

It is preferable to hand over the treasure to the heirs of the original owners if they are known; otherwise, it should be placed in the Muslim treasury or used for public welfare.

A distinction must be made between a pre-Islamic treasure (rikaz) and a treasure belonging to Muslims. The latter is considered lost property (luqatah) and its rules apply to it.