We prayed in a mosque and did not know that it had been built on an old cemetery. What is the validity of our prayer?

Question:
He says: Honorable Shaykh, may Allah grant you success. We are in the UAE, and we found a mosque there a few years ago. It had been built on an old cemetery, and we did not know until some time had passed. Is our previous prayer valid?

Answer:
How did you find a mosque on an old cemetery? Do you mean adjacent to the cemetery? Separated from the cemetery? If it is separated from the cemetery by a road or a boundary, there is no harm. However, if it is attached to the cemetery, with its wall touching the cemetery, then the prayer is not valid. You must verify this. It is not enough for you to simply repeat the prayer. You must go there in pairs and explain this to them, and seek the help of the scholars there to work on rectifying the situation.