Finding lost dogs; returning to true owner

Taking in a lost dog is a great thing to do but what happens when the dog's owner shows up? Recently I heard of this happening to someone who had found the dog three years ago. The dog had been left with friends and had run off. The original owner did everything they could to find it. Three years later they spotted the dog in its new owner's car and left a note under the windshield wiper.

This can be heartbreaking if the original owner wants the dog back. In many cases, they won't, they will have replaced the dog and they'll be happy just to know that their dog is ok after all. But if they do, the right thing to do is to return the dog to the original owner. There is no law of finders keepers. In fact the ancient, common law of trover (from the Fr. trouver: to find) is that if you find something, you can keep it until the true owner claims it. There is no time limit on this rule.

That seems harsh perhaps, especially to new owners who have rescued a stray dog, but think about from the point of view of the original owner.