94 have exceeded a reasonable time. The foregoing has caused the victims insecurity, impotence and anguish. 95. More than 22 years after the massacre and 10 after the corresponding investigations were opened, the State has not investigated the facts or identified, prosecuted and punished those responsible. This constitutes a situation of impunity, which contravenes the State’s aforementioned obligation, harms the victims, and encourages the chronic repetition of the human rights violations in question.263 96. On many occasions, this Court has referred to the right of the victims’ next of kin to know what happened and the identity of the State agents responsible for the respective facts.264 As the Court has indicated, taking into account the aggravating circumstances of the instant case: “whenever there has been a human rights violation, the State has a duty to investigation the facts and to punish those responsible, […] and this obligation must be complied with seriously and not as a mere formality.”265 97. The victims of human rights violations and their next of kin have the right to know the truth.266 This right to the truth has been developed by international human rights law267 and its recognition is an important measure of reparation. 98. In light of the above, and to repair this aspect of the violations committed, the State must conduct an effective investigation into the facts of the Plan de Sánchez massacre so as to identify, prosecute and punish the perpetrators and masterminds. The victims must have full access and competence to act at all stages and in all bodies of these investigations, in accordance with domestic law and the provisions of the American Convention.268 The result of the proceeding must be publicized so that Guatemalan society may know the truth. 99. The State must guarantee that the domestic proceedings to investigate, prosecute and punish those responsible for the facts will be effective. As the Court has noted in other cases, it must also abstain from using figures such as amnesty and prescription, and the establishment of measures designed to exclude responsibility, or measures intended to prevent criminal prosecution or suppress the effects of a conviction.269 263 Cf. Case of Tibi, supra note 3, para. 255; Case of the Gómez Paquiyauri Brothers, supra note 251, para. 228, and Case of the 19 Tradesmen, supra note 254, paras. 257 and 260. 264 Cf. Case of Tibi, supra note 3, para. 256; Case of the Gómez Paquiyauri Brothers, supra note 251, para. 229, and Case of the 19 Tradesmen, supra note 254, para. 258. 265 Cf. Case of Tibi, supra note 3, para. 256; Case of the Gómez Paquiyauri Brothers, supra note 251, para. 229, and Case of the 19 Tradesmen, supra note 254, para. 258. 266 Cf. Case of Tibi, supra note 3, para. 257; Case of the Gómez Paquiyauri Brothers, supra note 251, para. 230, and Case of the 19 Tradesmen, supra note 254, para. 261. 267 Cf. Case of Tibi, supra note 3, para. 257; Case of the Gómez Paquiyauri Brothers, supra note 251, para. 230, and Case of the 19 Tradesmen, supra note 254, para. 261. 268 Cf. Case of Tibi, supra note 3, para. 258; Case of the Gómez Paquiyauri Brothers, supra note 251, para. 231, and Case of the 19 Tradesmen, supra note 254, para. 263. 269 Cf. Case of Tibi, supra note 3, para. 259; Case of the Gómez Paquiyauri Brothers, supra note 251, para. 232, and Case of the 19 Tradesmen, supra note 254, para. 263.