investigations from obtaining relevant information: (a) to determine whether Mr. Osorio Rivera really entered the said Base; (b) to corroborate the conditions in which he remained there; (c) to compare versions concerning the alleged release, because it was carried out by a sergeant who has not been identified in the proceedings, and (d) to identify and prosecute the other persons who could have participated in the enforced disappearance of Jeremías Osorio Rivera. As this Court has indicated, the State authorities are obliged to collaborate in the gathering of evidence to achieve the objectives of the investigation, and to abstain from taking steps that imply obstructions to the progress of the investigative process. 320 In addition, the State cannot hide behind the lack of evidence of the existence of the documents requested, but, to the contrary, must justify the refusal to provide them, proving that it has taken all available measures to verify that the information requested does not exist. 321 In this case, the State has not justified its refusal to provide the information requested or described the measures it took to obtain this information. 196. As established previously, the first oral proceeding concluded on December 17, 2008, with the delivery of the judgment by the National Criminal Chamber, deciding to acquit Lieutenant Tello Delgado of the charges he was accused of, considering that “the detention and transfer of the victim by the accused has been proved, as well as the fact that, to date, the latter has not been located, which constitutes suffering for his family members and which has evidently been affecting them for more than 17 years; however, there are serious doubts about the responsibility of the accused in the events of which he is accused; a doubt which is favorable to him in application of the constitutional principle of in dubio pro reo.” 322 This judgment was declared null, considering that the evidence had not been assessed properly (supra para. 96). 197. In the second oral proceeding Lieutenant Tello Delgado was again acquitted, because reasonable doubts existed about his responsibility. 323 Regarding this judgment, it was decided that it was not null and “it was a clear case of doubt, in the face of the inculpatory and exculpatory evidence; in other words, a case of in dubio pro reo; so that the accused must be acquitted.” 324 In this regard, the court described, on the one hand, the “indications of the perpetration of the offense,” namely: (1) it is not credible that the accused was unaware that the victim was considered a subversive; (2) the detention and release of Gudmer Tulio Zárate Osorio and another six individuals who had been detained, other than the victim; (3) that the accused did not provide the name of any of the members of the patrol on the date of the events, individuals who detained the victim and who, together with the accused, took him to Cajatambo, and (4) that the great distance between Cajatambo and the domicile of the victim was not taken into account, so that the victim, instead of going home would have gone to the home of his sister, Silvia Osorio, who lived a Military Base (evidence file, volume x, annex 80 to the State’s answering brief, folio 4985); Judgment delivered by the National Criminal Chamber on December 17, 2008 (evidence file, volume IX, annex 20 to the State’s answering brief, folio 4720), and Judgment delivered by the National Criminal Chamber on November 4, 2011 (evidence file, volume VII, annex 14 to the brief with motions, arguments and evidence, folio 3615). 320 Cf. Case of García Prieto et al. v. El Salvador, supra, para. 112, and Case of Gudiel Alvarez et al. (“Diario Militar”) v. Guatemala, supra, para. 251. 321 Cf. Case of Gomes Lund et al. (Guerrilha Do Araguaia) v. Brazil. Preliminary objections, merits and reparations. Judgment of November 24, 2010. Series C No. 219, para. 211, and Case of the Massacres of El Mozote and nearby places v. El Salvador, supra, para. 257. 322 Judgment delivered by the National Criminal Chamber on December 17, 2008 (evidence file, volume IX, annex 20 to the State’s answering brief, folio 4750). 323 Cf. Judgment delivered by the National Criminal Chamber on November 4, 2011 (evidence file, volume IX, annex 12 to the State’s answering brief, folios 4506 to 4582). 324 Supreme final judgment R.N. No. 1071-2012 issued by the Transitory Criminal Chamber of the Supreme Court of Justice of the Republic on April 17, 2013 (evidence file, volume XII, annexes to the brief with the State’s final arguments, folios 5419 to 5434). 72