iPhone (deleted) pictures

Our son deleted all of his senior year pictures from his iPhone. As far as we know, he did not back up anything. On top of that, he took pictures "over" the deleted ones. (After he did deleted them, we went to an Apple store right away. They just told him that the pictures were "gone." No one mentioned that they might be there, but do NOT take more pictures.)

Any help you can give us will be greatly appreciated.

Thank you -

Carolyn Eagle