68 the States’ international obligations must be performed in good faith, and states cannot invoke their domestic 236 law as an excuse for non-compliance with international law. This principle also applies in the area of human rights, which the universal, regional and inter-American human rights bodies have recognized on numerous occasions. Regardless of whether Chile’s domestic laws allow the use of anonymous witnesses in trials in which the defendant is charge with violations criminalized under its Anti-Terrorism Act, the Commission must determine whether, in a given case, witness protection measures are compatible with the State’s international obligations under the American Convention. 243. The Commission observes that the Chilean courts used anonymous witnesses in two of the criminal trials examined in this report. 244. In the trial prosecuted against Pascual Pichún and Aniceto Norín, testimony was taken from two anonymous witnesses. During the first phase of the case up to the adoption of the verdict of acquittal, the identity of these witnesses was not revealed, either to the accused or to their attorneys; during the second phase of the case, the trial itself, the attorneys were told the identity of the protected witnesses, but were told they could not reveal their identity to the accused. At the oral proceedings, the witnesses testified behind a screen that hid them from all those in attendance, except for the judges. A written copy of their statements was provided to the defense attorneys beforehand, who had an opportunity to cross-examine them, as the record of the case shows. 245. The Court took those statements into account when determining both the existence of the crimes and the defendants’ guilt. In effect, the statements were weighed together with other evidence, as follows: in the case of the crime of threatening terrorist arson against the owners and managers of the Nancahue tree farm, the evidence the court considered was the testimony of “protected witness No. 1”, as well as the testimony of five other witnesses, an expert and two documents; in the case of the “terrorist arson” at the home of Juan A. Figueroa, the evidence the court considered included that given by two anonymous witnesses, six other witnesses, five experts and one document. 246. Through their attorney, the defendants requested that the identity of protected witness No. 1 be revealed so that criminal cases could be brought against him for perjury. However, in Consideranda 23 of its verdict, the Court did not accede to their request on the grounds of the “nature and seriousness of the crimes established in this ruling.” The petitioners reported –and the State did not contest- that once Secret Witness No. 1 had testified, the defense attorneys offered to enter new evidence to refute the anonymous witness’ assertions and to raise questions as to his credibility. The Court dismissed their offer and gave no explanation other than its discretionary authority to either allow or disallow evidence. 247. Then, in Consideranda 16, the Court describes the evidence that convinced it that Pascual Pichún was the material author of the crime of threats. It listed that evidence as follows: the testimony given by Protected Witness No. 1, who told the court that Pascual Pichún had told him that he planned to set a fire; Juan Agustín Figueroa Elgueta and Juan Agustín Figueroa Yávar, manager and owner of the Nancahue tree farm, who were those directly aggrieved; Osvaldo Carvajal Rondanelli, who told the court that his private investigations had found that Pascual Pichún was a member of the Coordinadora Arauco Malleco, although he did not provide any information as to his material participation in the threats. Another factor taken into account was an undated letter signed by Pascual Pichún and a check that Juan A. Figueroa had made out to Pascual Pichún in February 2001. 248. The case prosecuted against Víctor Ancalaf also used the testimony of anonymous witnesses, under the inquisitorial procedural system in force in the Concepción region at the time of the 236 See Vienna Convention on the Law of Treaties, 1155 U.N.T.S. 331, Article 27. See also I/A. Court H.R., Advisory Opinion OC-14/94, International Responsibility for the Promulgation and Enforcement of Laws in Violation of the Convention (Articles 1 and 2 of the American Convention on Human Rights), 9 December 1994, Ser. A Nº 14, para. 35; Greco-Bulgarian “Communities”, Advisory Opinion, 1930, P.C.I.J., Series B, Nº 17, p.32; Treatment of Polish Nationals and Other Persons of Polish Origin or Speech in the Danzig Territory, Advisory Opinion, 1932, P.C.I.J., Series A/B, Nº 44, p. 24; Free Zones of Upper Savoy and the District of Gex, Judgment, 1932, P.C.I.J., Series A/B, Nº 46, p. 167. IACHR, Report on Terrorism and Human Rights, OEA/SER.L/V/II.116, Doc. 5 rev. 1, corr., October 22, 2002, paragraph 42, footnote 109.