2 3. The brief of June 25, 2009, whereby the next of kin of Ernesto Castillo Páez asked the Court “to convene a hearing on monitoring the [judgments, and also] to issue an order declaring that Peru had still not complied fully with the Court’s decisions.” 4. The brief of June 29, 2009, whereby the Republic of Peru (hereinafter “the State” or “Peru”) presented a communication from the office of the Supranational Special Public Attorney regarding the “obligation to investigate, prosecute, and punish those responsible for the violation perpetrated in the Castillo Páez case.” 5. The notes of the Secretariat of the Court (hereinafter “the Secretariat”) of December 14, 2009, February 17, 2010, and February 2, 2011, informing the State that, in accordance with the second operative paragraph of the Order issued by the Court on April 3, 2009 (supra second having seen paragraph), it must present by July 15, 2009, at the latest, “a report indicating all the legal, administrative or other measures taken by its authorities to ascertain the whereabouts of the youth Ernesto Castillo Páez.” The Secretariat also informed the State that the brief presented on June 29, 2009, “d[id] not contain the information requested by the Court in the said Order [...]” and, consequently, on the instructions of the President of the Court, it was asked to submit the said report. CONSIDERING THAT: 1. One of the inherent attributes of the jurisdictional functions of the Court is to monitor compliance with its decisions. 2. Peru has been a State Party to the American Convention on Human Rights (hereinafter “the American Convention” or “the Convention”) since July 28, 1978, and accepted the contentious jurisdiction of the Court on January 21, 1981. 3. Under Article 67 of the American Convention, the State must comply fully and promptly with the judgments of the Court. Similarly, Article 68(1) of the American Convention stipulates that “[t]he States Parties to the Convention undertake to comply with the judgment of the Court in any case to which they are parties.” To this end, the State must ensure implementation at the national level of the Court’s decisions in its judgments.1 4. The obligation to comply with the decisions in the Court’s judgments corresponds to a basic principle of the law of the international responsibility of the State, supported by international case law, according to which a State must comply with its international treaty obligations in good faith (pacta sunt servanda) and, as this Court has already indicated and as established in Article 27 of the 1969 Vienna Convention on the Law of Treaties, a party may not invoke the provisions of its 1 Cf. Baena Ricardo et al. v. Panama. Competence. Judgment of November 28, 2003. Series C No. 104, para. 60; Case of the Ituango Massacres v. Colombia. Monitoring compliance with judgment. Order of the President of the Inter-American Court of Human Rights of December 22, 2010, third and fourth considering paragraph, and Case of Tibi v. Ecuador. Monitoring compliance with judgment. Order of the Inter-American Court of Human Rights of March 3, 2011, third considering paragraph.