In such a case, it is obligatory to
search for the person to whom this money is due and give it back. However, since you do not know where this man works or lives; you must give the dinars mentioned in the question in Sadaqah (voluntary charity) on behalf of the person to whom they are due. However, if this Christian person appears one day and demands his money, inform him of what you did with the money. They may then agree to it or, if they do not, you must give them back their dinars (Part No. 14; Page No. 71) and the reward of the Sadaqah will be yours. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.