The notifications when served shall be returned forthwith by the officer serving them, either in person or by registered or certified mail, to the jury commissioner, who shall make out a list of the persons served, with their names, occupations, and residence appearing thereon and send the list, together with the notification, to the clerk of the court from which the notice came. Upon each list sent, the jury commissioner shall certify that all the names thereon contained are persons who have been investigated by him or her personally, or through his or her assistants, and found in his or her judgment to be persons well qualified to serve as jurors.