O.C.G.A. § 9-14-1: Who may seek writ.

(a) Any person restrained of his liberty under any pretext whatsoever, except under sentence of a state court of record, may seek a writ of habeas corpus to inquire into the legality of the restraint.

(b) Any person alleging that another person in whom for any cause he is interested is kept illegally from the custody of the applicant may seek a writ of habeas corpus to inquire into the legality of the restraint.

(c) Any person restrained of his liberty as a result of a sentence imposed by any state court of record may seek a writ of habeas corpus to inquire into the legality of the restraint.