Fisherman friend of mine found a tackle box with a S&W M&P 9mm in it along with assorted lures, etc.
He was way back in a wilderness area flyfishing when he found it and hadn't seen another person all day. No ranger stations or anything else nearby. I think he still has it, never fired it, and at a loss. I told him if it is a concern see if a LEO will run it for him, the owner may have reported it stolen. Or he may have been so embarrassed he wrote it off.