238. Even though dozens of people were questioned during the judicial investigation, 271 this Court considers that those efforts were insufficient to ensure due diligence in an investigation of forced disappearance, because it is necessary to investigate the elements that emerge from the said statements so that a more thorough investigation is conducted. 239. Furthermore, the Court notes that the judicial decisions did not take into account the different testimonies affirming the participation of State agents in Mr. Gonzalez Medina’s disappearance and his detention in several State security agencies (supra paras. 155 to 164), without including any grounds for not considering them important or reliable. 272 The only analysis the Investigating Court made of any element of evidence that it did not consider reliable is that of the testimony given by the brother of a Captain who had seen Narciso González Medina in the Intelligence Department of the Dominican Air Force (A-2). The two main reasons why the domestic judicial organs doubted the “veracity and credibility” of this testimony were: (a) the denial by the State authorities who could have been involved, and (b) the fact that the deponent had not been an eye witness, and his statement could not be confirmed owing to the death of his brother who was the eyewitness. Regarding the first of these reasons, the Court refers back to its previous findings (supra para. 161). 273 In addition, the Court notes that, by using this judicial reasoning that doubts the “veracity and credibility” of the testimony of the deceased brother of that Captain because it contradicts the statements of senior officials who could have been involved, the judge is indirectly granting full credibility to the statements of those superior officials without motivating his assessment and without any record in the judicial decisions that he had made any additional verification in this regard. Regarding the fact that the brother of the deceased Captain was not an eyewitness, this Court notes that the said deponent gave reasons why he suspected that his brother’s death was not due to a car accident, but rather he could have been killed because he had seen Mr. González Medina in the A-2. The Court has verified that a series of circumstances relating to the death of his brother were not examined such as the place of the accident and the vehicles involved, which could have been investigated 274 to clarify or reject the relationship of this fact with the forced disappearance of Mr. González Medina. 271 Witness Eduardo Sánchez Ortiz, who was the Investigating Judge of the investigation as of April 1998, emphasized that all those involved in the complaint were questioned and other persons, and that “each person was questioned about their version of the disappearance of Professor Narciso González […].” Testimony given by witness Eduardo Sánchez Ortiz before the Inter-American Court during the public hearing held in this case on June 28, 2011. 272 The Investigating Court concluded that it had “no knowledge of the location of Professor Narciso González, or his corpse, and no one has provided reliable testimony about where he is, or that they saw him at the time of his disappearance or subsequently, which would provide any idea about his whereabouts or the presumed destruction of his life.” The said court also stated that “there [was] no reliable witness to confirm the abduction and its circumstances and, during the investigation, only one piece of information was given and it cannot be confirmed.” For its part, the Review Chamber affirmed that “from the analysis of the documents in the case file, and from examining the answers given by the other deponents to the questions of the Investigating Court, in the capacity in which they were summoned, it is understood that it is not necessary to question them before this jurisdiction, in the understanding that they did not provide any new element or indication that would change the status of the proceedings.” Cf. August 24, 2001, ruling of the Investigating Court, supra note 105, folio 4542, 4548 and 4549, and decision of December 18, 2002 of the Santo Domingo Review Chamber, supra note 138, folio 4603. 273 In this regard, the Court also refers to similar considerations expressed in relation to the Review Chamber’s analysis of the testimony of a “supplier” of the Armed Forces (supra paras. 159 to 161). 274 This Court has specified the guiding principles that must be observed in an investigation into a violent death. According to the Inter-American Court’s case law, the State authorities that conduct an investigation of this type must try, at least, inter alia: (a) to identify the victim; (b) to recover and preserve the probative material related to the death in order to assist any potential criminal investigation of those responsible; (c) to identify possible witnesses and obtain their statements in relation to the death investigated; (d) to determine the cause, manner, place and time of death, as well as any pattern or practice that could have caused the death, and (e) to distinguish between natural death, accidental death, suicide and murder. In addition, it is necessary to investigate the scene of the crime thoroughly; and autopsies and analyses of human remains must be conducted rigorously, by 75