¶1This is a proceeding by habeas corpus in which Amos S. Kaufman, the petitioner, alleges he is illegally restrained of his liberty in the State penitentiary by the warden thereof. The warden, in his return avers that, at the April term, 1881, of the criminal court within and for Pettis county, said petitioner was convicted of larceny in a dwelling house, in said county, and by the judgment of the court was sentenced to confinement in the penitentiary for the term of two years, a copy of which sentence and judgment he files with his return as his authority for holding the petitioner. The said judgment of said criminal court, under which defendant is held, being a final judgment rendered by a court having jurisdiction n such matters, our duty in the premises is prescribed by section '2648, Revised Statutes 1879, which provides that in proceedings by habeas corpus, the court or magistrate before which the case is pending, shall “ forthwith remand the party, if it shall appear that he is detained in custody by virtue of the final judgment, order or decree of any competent court of criminal or civil jurisdiction.” Under this plain provision of the statute, which interprets itself, it is our duty to remand the petitioner, which is hereby done.
¶2The only ground urged upon us for the discharge of the petitioner, is base'd upon the alleged fact, and for the first time here asserted, that the petitioner, at the time o *590bis conviction, was under the age of eighteen years, and was not, therefore, liable to be sentenced to confinement in the penitentiary. As this fact does not appear in the record, and was not made known in the nisi prius court, we know of no law which would authorize us to try the question as to whether the fact asserted is true or false. The duty of trying this question belonged to the court where the trial of petitioner was pending, and in which the judgment was rendered, and the petitioner should have given that court an opportunity of performing the duty by raising the question of non-age there, instead of undertaking to have it investigated here. State v. Gavner, 30 Mo. 44; Ex Parte Toney, 11 Mo. 661. An order will be made remanding the petitioner and dismissing the writ,