-14exceed the limits of the dispute established by the Commission and the State Party. Consequently, and with regard to the said persons, the Commission must play the role of the Attorney General’s Office in their representation and not the petitioners.9 58. In this regard, the Court observes that, in its application brief, the Commission indicated that it would act on behalf of the next of kin of 13 of the alleged victims who did not have representation, while the non-governmental organizations, the Comisión Colombiana de Juristas, CEJIL and ASFADDES, stated in their requests and arguments brief that they would act on behalf of the next of kin of 32 of the alleged victims. Subsequently, while the case was being processed before the Court, the representatives submitted powers of attorney granted by the next of kin of other alleged victims. 59. In relation to the above considerations regarding the participation of the victims, their next of kin or their representatives (supra paras. 53 to 56), it should be clarified, that the representatives act on behalf of the next of kin who have granted the corresponding valid power of attorney and that, in the case of those who are not represented or who lack such representation, this is assumed by the InterAmerican Commission, which must protect their interests and ensure that they are represented effectively at the different procedural stages before the Court, “as guarantor of the public interest under the American Convention, to ensure that they have the benefit of legal representation” (Art. 33(3) of the Rules of Procedure of the Court). This is the Court’s understanding in the instant case, and the assessments and decisions on merits and possible reparations will be made independently of the organization, institution or persons that are exercising specific representation, in keeping with the Court’s inherent functions as an international human rights court and in application of the pro persona principle. VI EVIDENCE 60. Before examining the evidence received, the Court will make some observations in light of the provisions of Article 44 and 45 of the Rules of Procedure, which are applicable to the specific case, most of which have been developed in its case law. 61. The adversary principle, which respects the right of the parties to defend themselves, applies to matters pertaining to evidence. This principle is embodied in Article 44 of the Rules of Procedure, as regards the time at which the evidence should be submitted to ensure equality between the parties.10 62. According to the Court’s practice, at the commencement of each procedural stage, the parties must indicate the evidence they will offer at the first opportunity they are given to communicate with the Court in writing. Moreover, in exercise of the discretional powers included in Article 45 of its Rules of Procedure, the Court or its President may request the parties to provide additional probative elements as helpful evidence; and this shall not provide a new opportunity for expanding or 9 Cf. brief with preliminary objections, answer to the application and with observations on the requests and arguments brief (merits file, tome II, p. 36, folio 393). 10 Cf. Case of Blanco Romero et al. Judgment of November 28, 2005. Series C No. 138, para. 37; Case of García Asto and Ramírez Rojas. Judgment of November 25, 2005. Series C No. 137, para. 82, and Case of Gómez Palomino. Judgment of November 22, 2005. Series C No. 136, para. 45.