How can one absolve oneself of a financial debt owed as blood money (Diyya) to a person who is absent or unreachable, and is it permissible to deposit the money in the Muslim Public Treasury (Bayt al-Mal)?

Whoever owes a debt to someone must strive to find the rightful owner by every possible means. If he despairs of finding him or his heirs, he may donate the amount to the poor, the needy, and charitable causes, with the intention of giving charity on behalf of the owner. If the owner of the money appears thereafter, he may either approve the charity, and thus the debtor's responsibility is cleared, or else the debtor must fulfill his right to him, and the reward for the charity remains for the debtor.