Civil Code (Cap. 16), article 322

322. (1) Save as otherwise provi ded by law, the owner of a thing has the right to rec over it from any possessor. (2) A possessor who, after being notified of the judicial demand for the recovery of the thing ceases of his own act, to possess such thing, is bound, at his own expense, to regain possession of the thing for the plaintiff, or, if unable to do so, to make good its value, unless the plaintiff elects to proceed aga inst the actual possessor. Ownership of land carries with it ownership of what is above and under it.