assumed in the treaty. Although the Commission indicated Article I(c) of the IACFDP, concerning the duty of cooperation between States to prevent, punish and eradicate the forced disappearance of persons, it did not specify the rationale for this violation and the Court does not find a sufficient basis to examine the alleged failure to observe this provision. 138. Given the duty to investigate, once State authorities learn of an incident, they must initiate de officio and without delay a serious, impartial, and effective investigation171 that is undertaken with all legal means available and is directed to ascertain the truth.172 139. While the duty to investigate is an obligation of means and not of results, it must be undertaken by the State “in a serious manner and not as a mere formality preordained to be ineffective. An investigation must have an objective and be assumed by the State as its own legal duty, not as a step taken by private interests that depends upon the initiative of the victim or his family or upon their offer of proof.”173 Due diligence in an investigation “requires the investigating body to carry out all measures and investigations necessary to try and obtain the required result.”174 140. Article 8(1) of the Convention requires that the facts investigated in criminal proceedings be resolved within a reasonable time since in certain cases “a prolonged delay in itself may constitute a violation of the right to a fair trial.”175 B.2. Examination of the actions taken in this case 141. Based on the above-mentioned points and others that are more specific that will be indicated, the Court will analyze, in the context of the effective date of its jurisdiction,176 the relevant facts of the case. It will limit its examination to the arguments of the Commission and the representative on the shortcomings in the State’s conduct, which refer to: (1) the application of the Expiry Law; (2) the lack of diligence in its actions; (3) the failure to observe a reasonable period, and (4) the violation of the right to the truth. B.2.1 Obstruction of the investigations by application of the Expiry Law Cf. Case of Velásquez Rodríguez v. Honduras. Merits, para. 177 and Case of Garzón Guzmán et al. v. Ecuador, para. 69. 171 Cf. Similarly, Case of Juan Humberto Sánchez v. Honduras. Preliminary Objection, Merits, Reparations and Costs. Judgment of June 7, 2003. Series C No. 99, para. 127 and Case of Barbosa de Souza et al. v. Brazil. Preliminary Objections, Merits, Reparations and Costs. Judgment of September 7, 2021. Series C No. 435, para. 128. 172 Cf. Case of Velásquez Rodríguez. Merits, para. 177 and Case of Barbosa de Souza et al. v. Brazil, para. 128. 173 Cf. Case of the Serrano Cruz sisters v. El Salvador. Merits, Reparations and Costs. Judgment of March 1, 2005. Series C No. 120, para. 83 and Case of Garzón Guzmán et al. v. Ecuador, para. 67. 174 Cf. Case of Hilaire, Constantine and Benjamin et al. v. Trinidad and Tobago. Merits, Reparations and Costs. Judgment of June 21, 2002. Series C No. 94, para. 145 Case of González et al. v. Venezuela, para. 185. 175 In view of the date of their deaths and the effective date of the jurisdiction of the Court (supra paras. 12 and 55 to 60), the Court considers that it is not appropriate to examine the violations of human rights regarding Ms. Reyes, Ms. Maidanik and Ms. Raggio. 176 39