No demand for the extradition of a person charged with a crime in another state shall be recognized by the governor unless in writing and accompanied by a copy of an indictment found or by information supported by affidavit in the state having jurisdiction of the crime, or by a copy of an affidavit made before a magistrate there, together with a copy of any warrant which was issued thereon. The indictment, information or affidavit made before the magistrate must substantially charge the person demanded with having committed a crime under the law of that state; and the copy must be authenticated by the executive authority making the demand, which shall be prima facie evidence of its truth.