If a grave and a mosque are in the same place, is the grave to be exhumed or the mosque demolished, and what is the criterion for this?

Question:
Honorable Shaykh, may Allah grant you success. A questioner says: If there is a grave in a mosque, is the mosque to be demolished or the grave exhumed?

Answer:
If the mosque was built first and the grave was a later addition, then the grave is exhumed and the mosque is cleared of it. But if the grave was there first and the mosque was built over it, then the mosque is demolished. Yes.