Possession is nine-tenth of the law.
https://en.wikipedia.org/wiki/Possession_is_nine-tenths_of_the_law
Although the principle is an oversimplification, it can be restated as: "In a property dispute (whether real or personal), in the absence of clear and compelling testimony or documentation to the contrary, the person in actual, custodial possession of the property is presumed to be the rightful owner. The rightful owner shall have their possession returned to them; if taken or used. The shirt or blouse you are currently wearing is presumed to be yours, unless someone can prove that it is not."