He collected sums due to some persons from others but was not able to give the first their rights

Fatwa no. 21715 All praise be to Allah Alone, and peace and blessings be upon the Last of the Prophets. To proceed:The Permanent Committee for Scholarly Research and Ifta' reviewed the question received by His Eminence the Grand Mufty from His Eminence the Director of Da`wah and Guidance Center in Al-Dammam, no. 22/1/1295, dated 25 Sha`ban, 1421 A.H., including a Fatwa request sent by His Excellency the Commander of the Military Police in the Eastern Province Border Guard, (Part No. 11; Page No. 213) and referred to the Committee from the Secretariat General of the Council of Senior Scholars, no. 5458, dated 1 Ramadan, 1421 A.H. He asked His Excellency the following question:"We would like to notify Your Eminence that we had a department called Financial Claims, which was newly structured in 1417 A.H. Before that year, we had a sum of 9,705 riyals left. This sum was collected from some individuals for the interest of other citizens. We attempted many times to know who the citizens were, for whom this sum was collected or the individuals paying this sum, but we could not identify any of them. Thus, we hope you will inform us whether we can spend this sum in building and repairing the Masjids (mosques) in the Border Guard. May Allah safeguard and protect you."

Upon considering the Fatwa request, the Committee answered that the one who collected the sum should exert all possible efforts to know the identity of the payers and payees, and this includes publicizing this matter. If they failed to identify them after exerting effort, they should pay the sum as Sadaqah (voluntary charity) intending the owners of this money to reap the reward, or they can use it in a charitable project.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family and Companions.