If he truly has no information about his detention, he may seek a writ of habeas corpus.
Quote Quoting OCGA Sec. 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.
Quote Quoting OCGA Sec. 9-14-6. Form of writ
The writ of habeas corpus may be substantially as follows:

Code:
                   IN THE ______ COURT OF ______ COUNTY                       
 
                               STATE OF GEORGIA                                
 
   A.B.,                                  )
         Petitioner                       )
                                          )
            v.                            )      Civil action
                                          )
   C.D.,                                  )      File no.      
         Respondent                       )
 
 
                             WRIT OF HABEAS CORPUS                             

   To C.D.:
      You are hereby commanded to produce the body of      , alleged to be 
   illegally detained by you, together with the cause of the detention, before 
   me on the ____ day of _____, ____, at __:__ _.M., then and there to be 
   disposed of as the law directs.
 
   Given under my hand and official signature, this _____ day of ____, ____.
                                                                 
                                                                ________________
                                                                 Judge
See OCGA Sec. 19-14-1 et seq.