Is it obligatory to give in charity to the poor the money whose owner could not be found, or is it permissible to give it in charity to the rich as well, knowing that voluntary charity is permissible for the rich?

If a person has money whose owner he does not know, he must donate it to the poor and needy. It is not permissible for him to give it to the rich as charity, because he is like an agent for his Lord in dispensing it. Al-Ghazali explicitly stated that it is not permissible to give illicit money whose owner is unknown to the rich. This ruling applies to all money whose owner is unknown, even if it was acquired through permissible means.