If I found a pistol in a restroom, no one would hear about it
About ten years ago, some guy with a carry permit got sick at a Chuck E Cheese in our area and went to the restroom. He left his loaded pistol in there. Some six year old found it there and carried it back to the ball pit, where it was found later by a three year old. Needless to say, that generated a lot of press.
Firearms issued to LEO’s are registered by serial number. The FBI would search for the weapon once it was reported to them as lost or stolen. Not a good idea to play finders keepers with a misplaced firearm registered to a police department.