Is it permissible to move the soil of a person buried with other deceased individuals in a single grave, whose descendants are unknown, and place it in the town's cemetery, then build a separate tomb over it and visit it to pray for him?

It is not permissible to take any soil from the grave to erect a symbolic grave for the deceased, nor to transfer their body or bones, unless the deceased has completely disintegrated and turned into dust. For the deceased has sanctity, and it is not permissible to exhume a grave merely to transfer the body to be buried next to relatives or in their homeland. Furthermore, the Prophet (peace be upon him) and his noble companions did not build symbolic graves for the deceased.