of the State and does not depend on the procedural initiative of the victim or their next of kin, or on their provision of probative elements.283 194. This Court has also indicated that, in a democratic society, the true facts of grave human rights violations must be known. This is a reasonable expectation that the State must satisfy,284 on the one hand, by the obligation to investigate human rights violations ex officio and, on the other, by publicizing the results of the investigative and criminal proceedings.285 This requires the State to determine by means of legal proceedings the patterns of joint actions, and all those who, in different ways, took part in the said violations and their corresponding responsibilities,286 and to provide reparations to the victims in the case. Consequently, on previous occasions, the Court has considered that the authorities in charge of the investigation have the duty to ensure that, during its course, they assess the systematic patterns that allowed grave human rights violations such as those that occurred in this case to be committed.287 In order to guarantee its effectiveness, the investigation must be conducted taking into account the complexity of this type of facts and of the structure in which those probably involved were incorporated, based on the context in which the facts took place, thus avoiding omissions in the collection of evidence and in following up on logical lines of investigation.288 Consequently, the State authorities are obliged to collaborate in the collection of evidence to achieve the goals of the investigation, and to abstain from taking measures that would obstruct the progress of the investigative procedure.289 B.1. Failure to investigate the massacres that occurred in the Río Negro chapel and at Los Encuentros 195. In this Judgment, it has been established that the State has not investigated the acts that occurred during the massacres committed in the Río Negro chapel and at Los Encuentros (supra para. 88). In this regard, the Court considers it pertinent to indicate that, during the criminal proceedings opened in 1993 to investigate the massacres committed on Cerro Pacoxom and in Agua Fría (infra paras. 197 to 210), approximately 11 and 13 years after the events occurred, testimony was taken from a number of surviving victims who recounted the facts relating to the massacres in the Río Negro chapel and at Los Encuentros. In addition, the facts have been extensively addressed and documented by State entities, such as the Guatemalan Historical Clarification Commission, which, in its 283 Cf. Case of Velásquez Rodríguez v. Honduras, Merits, supra, para. 177, and Case of the Kichwa Indigenous People of Sarayaku v. Ecuador, supra, para. 265. 284 Cf. Case of Velásquez Rodríguez, Merits, supra, para. 181, and Case of Contreras et al. v. El Salvador, supra, para. 170. 285 Cf. Case of Las Palmeras v. Colombia. Reparations and costs. Judgment of November 26, 2002. Series C No. 96, and Case of Contreras et al. v. El Salvador, supra, para. 170. 286 Cf. Case of the La Rochela Massacre v. Colombia. Merits, reparations and costs. Judgment of May 11, 2007. Series C No. 163, para. 195, and Case of Gelman v. Uruguay, supra, para. 192. 287 Cf. Case of the La Rochela Massacre v. Colombia, supra, para. 156, and Case of Contreras et al. v. El Salvador, supra, para. 146. 288 Cf. Case of the Serrano Cruz Sisters v. El Salvador. Merits, reparations and costs. Judgment of March 1, 2005. Series C No. 120, para. 166, and Case of Contreras et al. v. El Salvador, supra, para. 146. 289 Cf. Case of García Prieto et al. v. El Salvador. Preliminary objections, merits, reparations and costs. Judgment of November 20, 2007. Series C No. 168, para. 112, and Case of Contreras et al. v. El Salvador, supra, para. 171. 72