66 subsequent disappearance of Mr. Radilla-Pacheco is added to another 121 inquiries is in agreement with the aforementioned elements. 222. However, the Tribunal points out that in order for an investigation of forced disappearance in the terms mentioned by the General Investigation Coordination to be carried out effectively and with due diligence,226 it requires the use of all means necessary to fulfill those actions and essential and timely inquiries promptly in order to clarify the fate of the victims and identify those responsible for their forced disappearance,227 especially, those regarding the present case. For this, the State shall provide the corresponding authorities with the logistical and scientific resources necessary for the gathering and processing of the evidence and, specifically, of the powers to access the appropriate documents and information for the investigation of the facts denounced and obtain indicia or evidence of the location of the victims.228 In this regard, the Court considers that, without detriment to the need to obtain and assess other evidence, the authorities in charge of the investigation shall pay special attention to the circumstantial evidence, the indicia, and the presumptions,229 which result especially important when dealing with cases of forced disappearance, “since this form of repression is characterized for trying to suppress any element that may be able to prove the arrest, whereabouts and fate of the victims.”230 The aforementioned is crucial in a case such as the present, in which the facts occurred approximately 35 years ago and in which the formal accusation of the facts was not filed immediately due to the specific context created by the State itself at that time. b.3) Other arguments regarding the effectiveness of the investigations 263. On the other hand, the representatives indicated that Mr. Zacarías Barrientos, who apparently witnessed many of the arrests and subsequent disappearances carried out during the seventies, was murdered in the year 2003 after offering his statement before the Special Prosecutors’ Office, therefore arguing that the State did not take the necessary measures for his protection. Likewise, they expressed that the State did not take the precautions necessary in order to maintain contact with Mr. Gustavo Tarín, who allegedly is an important witness in the elucidation of the facts. 224. The representatives also expressed that the investigation of the Special Prosecutors’ Office during its first years was characterized by an alleged lack of sensitivity upon treating the “survivors” and the “next of kin” when carrying out cabinet diligences and that on several occasions the “next of kin” reported that the agents of the Federal Public Prosecutors’ Office attached to the Special Prosecutors’ Office treated the plaintiffs, the collaborator, and the witnesses as criminals and not as victims. 226 Cf. Inter-American Convention on forced disappearance of persons, Articles I(b) and X and International Convention for the protection of all persons against forced disappearances. Article 12. 227 Cf. Case of Velásquez Rodríguez v. Honduras, supra note 24, para. 174; Case of Heliodoro Portugal v. Panama, supra note 24, para. 144, and Case of Anzualdo Castro v. Peru, supra note 44, para. 135. 228 Cf. Case of Tiu Tojín v. Guatemala, supra note 24, para. 77, and Case of Anzualdo Castro v. Peru, supra note 44, para. 135. 229 Cf. Case of Velásquez Rodríguez v. Honduras, supra note 24, para. 130; Case of Escher et al. v. Brazil, supra note 64, para. 127, and Case of Anzualdo Castro v. Peru, supra note 44, para. 38. 230 Case of Velásquez Rodríguez v. Honduras, supra note 24, para. 131; Case of Kawas Fernández v. Honduras, supra note 40, para. 95, and Case of Anzualdo Castro v. Peru, supra note 44, para. 38.