W. Va. Code § 53-4-1: When and by whom writ granted.

The writ of habeas corpus ad subjiciendum shall be granted forthwith by the Supreme Court of Appeals, or any circuit court, or any other court given power by any particular statute to grant the same, or any judge of either court in vacation, to any person who shall, by himself or by someone in his behalf, apply for the same by petition, showing by affidavit or other evidence probable cause to believe that he is detained without lawful authority.