Possession in nine-tenths of the law is an expression that ownership is easier to maintain if one has possession of something, or difficult to enforce if one does not.
Although the principle is an oversimplification, it can be restated as : “In a property dispute (whether real or personal), in the absence of clear compelling testimony or documentation to the contrary the person in actual, custodial possession of the property is presumed to be rightful owner.The rightful owner shall have their possession returned to them; if taken or used.