48 VIOLATION OF ARTICLE 9 FREEDOM FROM EX POST FACTO LAWS 150. As regards the violation of Article 9 of the Convention, the Commission alleged that: a) Peru has recognized that the crime of treason against the fatherland, regulated under Decree Law No. 25.659, is an aggravated form of the crime of terrorism, which is regulated under Decree Law No. 25.475. Both descriptions use unclear terms and are open to broad interpretation, making it difficult to distinguish one from the other. This violates the basic principle of criminal law regarding the need to define the nature of a crime precisely; b) Mr. Luis Alberto Cantoral-Benavides was tried for the crime of treason against the fatherland in the exclusive military jurisdiction “under the accusation that documents of a subversive nature were found in his possession.” Later, he was tried in the regular courts for the crime of terrorism, for allegedly having authored documents of this nature; and c) The ambiguity and similarity of the legal definitions of the crimes of treason against the fatherland and terrorism violate the legal principle established in Article 9 of the Convention, and led to double jeopardy in the case of Mr. Luis Alberto Cantoral-Benavides. 151. For its part, the State presented no arguments regarding the alleged violation of Article 9 of the Convention. * 152. * * Article 9 of the American Convention states that: No one shall be convicted of any act or omission that did not constitute a criminal offense, under the applicable law, at the time it was committed. A heavier penalty shall not be imposed than the one that was applicable at the time the criminal offense was committed. If subsequent to the commission of the offense the law provides for the imposition of a lighter punishment, the guilty person shall benefit therefrom. 153. In Decree Law No. 25.659, Articles 1, 2, and 3, and Decree Law No. 25.475, Articles 2 and 3, the crimes of treason against the fatherland and terrorism, respectively, are defined, and the punishment for each is established. In this regard, this Court has already established that “both Decree Laws (25.475 and 25.659) refer to conduct that is not precisely defined, meaning that it could be considered under either, according to the criteria of the Office of the Public Prosecutor Office, of the respective judges […] and of the ‘police’ [DINCOTE].”63 154. 63 The Court deems it pertinent to point out that: Castillo-Petruzzi et al. Case, supra note 9, para. 119 and Loayza-Tamayo Case, supra note 12, para. 68.