Lost pistol, not a ring found with metal detector

I was contacted a couple days ago by a gentleman whose grandson accidentally dropped a pocket pistol in the Muskingum River about a month ago while running bank lines for catfish. We made arrangements to meet and we hopped into a John boat and up the river we went. I just took my powerful magnet hoping we could just pick it up with that. I didn’t want to get into the river with my metal detector because I knew it would be “mucky” and cold. After several minutes and attempts with the magnet, it was obvious that I was going to have to go into the river. We met the following day with my wetsuit and MD’ing gear. Up the river once again to the spot in the river where they was sure it would be. I can only detect in water that is around chest high. We spent about an hour and exhausted the area I could comfortably reach. In a last attempt, I walked in chin deep water holding the metal detector out as far as I could in deeper water and finally got a shallow strong signal I was hoping for but there was no way I could scoop it up out there. Thankfully I had brought my magnet back out with me and we was able to get the magnet on the pistol!