- 24 - evidence provided by the parties should correspond to the substantial determination of the scope of the alleged violations of the Convention. 62. The State asked the Court not to consider “as valid evidence within the proceedings” a series of documents attached to the application regarding alleged accusations made by Mr. Cepeda Vargas and other leaders of the UP and the PCC, as well as by international organizations, before various national and international entities,67 because the validity of a document depends on its authenticity and that there is proof that it has been effectively received by the entity addressed. In addition, it objected to a letter addressed to the Ministry of Defense68 because it was undated. The Court considers that an acknowledgement of receipt does not constitute a formality that necessarily limits the validity of the document, so that its absence should not automatically imply the inadmissibility of the document in question. In this regard, these documents will be assessed together with the body of evidence, in relation to the fact they are intended to prove, in light of the State’s acknowledgement of international responsibility and considering the decisions taken by the domestic authorities. 63. Regarding the State’s clarifications concerning attachments 34 and 36 of the answer to the application,69 the Court will take them into account and consider them when assessing the evidence. Finally, as regards the observations of the State on attachments 146, 160, 162, and 165 of the brief with pleadings, motions and evidence, the Court observes that all these documents were issued by State authorities, so that the State had full access to them and, in any event, was able to submit the missing copies to the Court. Likewise, the Court considers that the State had access to attachment 27 to the application, given that this document was included in the criminal investigations. 64. The Court will assess the statements and opinions provided by the witnesses and expert witnesses at the public hearing and in sworn statements, when they are in keeping with the purpose defined by the President in the Order requiring them and the object of the instant case, bearing in mind the observations of the parties. 65. The statements of presumed victims are useful insofar as they can provide additional information on the violations and their consequences;70 but because they have a direct interest in this case, their statements will be assessed together with all the evidence in the proceedings.71 67 Namely: complaint of October 26, 1992, addressed to the Attorney General of the Nation by UP leaders; letter from the UP leaders to Amnesty International of July 27, 1993; request for protection addressed to the Minister of the Interior, of November 9, 1993; letter to the Attorney General of the Nation, Carlos Arrieta, dated October 26, 1992; letter to the Director of the Administrative Department of Security (DAS) of November 20, 1992; letter to the Minister of Defense, Rafael Pardo Rueda, undated; letter addressed to the Minister of the Interior by Human Rights Watch, dated November 6, 1999, and letter addressed to the President of the Republic by Amnesty International in November 1999. 68 Cf. letter from the Director of the weekly publication Voz to the Minister of Defense dated November 26, 1993 (evidence file, tome III, attachment 23 to the application, folios 1403 to 1404). 69 Cf. letter from Human Rights Watch addressed to the Ministry of the Interior, dated November 6, 1999 (evidence file, tome IV, attachment 36 to the application, folio 1983). 70 Cf. Case of the “White Van” (Paniagua Morales et al.) v. Guatemala, supra note 56, para. 70; Case of Radilla Pacheco v. Mexico, supra note 24, para. 93, and Case of Perozo et al. v. Venezuela, supra note 49, para. 103. 71 Cf. Loayza Tamayo v. Peru. Merits. Judgment of September 17, 1997. Series C No. 33, para. 43; Case of the Dos Erres Massacre v. Guatemala, supra note 57, para. 63, and Case of Radilla Pacheco v. Mexico, supra note 24, para. 93.