Disposing of money taken without right whose owner is unknown

The questioner:
He says: Honorable Shaykh, may Allah grant you success, I have money that I took without its right and without knowing its amount.

The Shaykh:
Yes.

The questioner:
I have money that I took without its right, and its amount is four thousand riyals. I do not know the owner of the amount, and after a period of time, I paid it to help in building a mosque. Will my conscience be cleared? And should I give charity from my salary every month to the owner of this wronged amount?

The Shaykh:
If you do not know its owner, you should spend it in the causes of good, and it should be the most disliked thing for its owner. If you paid it for a mosque, you will have the reward for that, and there is no harm. If it is good money from good earnings. If it is from evil earnings, such as riba (usury or interest), and you know that it is riba, do not put it in the mosque; put it in general projects other than the mosque. Yes.