If you notice that you cannot find a valuable ring that been given to you by your grandmother and you assume that you lost it. Then you see another student wearing what appears to be the ring you lost. You confront the person, and the person says that they found it on the floor of a local restaurant. You say that the ring is yours and provide pictures of the ring as evidence. The other student refuses to give it back to you.
In that scenario what is the principle of law?