was present in the area on the date and time of the young man’s death, or whether he often traveled in that area. 224. Sixth, there is evidence that at least by May 24, 2006, and March 3, 2007, two more individuals known as “Nito” and “Selvin” had been linked to the crime, (supra para. 113), and for this reason an investigation was opened to identify them. However, there is no record of any investigative activity in relation to the person known as “Nito”. As to the individual known as “Selvin”, on March 26 and April 10, 2008, the DICRI Investigators provided information about his identity and the exact address of a house he frequented, and on June 17, 2008, they carried out a raid, inspection and search procedure, but “with negative results.” 341 There is no record of any subsequent procedure, or that these individuals were summoned to testify before the Public Prosecution Service to obtain further information on the accusations against them. 225. Finally, the Court considers that, even though efforts were made to investigate the facts of Mr. A.A.’s death, there were omissions and delays in the procedures to gather evidence and the logical lines of investigation were not followed fully and thoroughly. Therefore, the investigation conducted in the domestic jurisdiction has not been diligent, thorough and effective. 226. Finally, the Court notes that, although nearly 10 years have elapsed since the events of this case occurred, and since the investigation began, the facts have not been clarified and truth of what happened has not been determined, affecting the right of Mr. A.A.’s relatives to obtain justice within a reasonable period. Therefore, the Court considers that a prolonged delay, as has occurred in this case, constitutes, in principle, a violation of judicial guarantees. The Court does not consider it necessary to analyze this point further. B.1.3. Protection for justice operators, investigators, witnesses and relatives of victims 227. The Court recalls that in order to ensure due process, the State must take all necessary measures to protect justice operators, investigators, witnesses and family members of victims from harassment and threats aimed at hindering the proceedings, preventing the elucidation of the facts and concealing those responsible. 342 Otherwise, those who investigate and those who could be witnesses would feel intimidated and frightened, and this would have a significant impact on the effectiveness of the investigation. 343 Indeed, the threats and intimidation suffered by witnesses in the domestic proceedings cannot be examined in isolation, but should be analyzed in the context of obstructions to the investigation of the case. Consequently, such acts become another means of perpetuating impunity and preventing the truth of what happened from being known. 344Furthermore, the Court considers that for an investigation to be effective, those responsible for it must be independent, both from a hierarchical and institutional point of view and also in practical terms, from the individuals implicated in the facts investigated. 345 228. From the file it is evident that a number of irregularities occurred during the criminal investigation, which reflect the fear felt by several witnesses identified in the case, 346 some of whom were closely associated with common crime in the area, which directly impacted the gathering and processing of evidence. 341 Cf. Request of the Office of the Human Rights Prosecutor to the Criminal Investigations Specialists of November 21, 2006 (File of attachments to submission brief, page 1122); Report of the Criminal Investigations Specialists to the Office of the Human Rights Prosecutor of March 26, 2008 (File of attachments to submission brief, pages 1169 to 1174); Report of the Criminal Investigations Specialists to the Human Rights Prosecutor of 10 April, 2008 (File of attachments to submission brief, pages 1177 and 1178), and the inspection, raid and search procedures of June 17, 2008 (File of attachments to submission brief, pages 1304 to 1306). 342 Cf. Case of Myrna Mack Chang v. Guatemala. Merits, Reparations and Costs. Judgment of November 25, 2003. Series C No. 101, para. 199, and Case of Gutiérrez and Family v. Argentina, supra, para. 118 343 Cf. Case of Kawas Fernández v. Honduras, supra, para. 106, and Case of Gutiérrez and Family v. Argentina. supra, para. 118. 344 Cf. Case of The Dos Erres Massacre, supra, para. 234, and Case of Gutiérrez and Family v. Argentina. supra, para. 119. 345 Cf. Case of Baldeón García v. Peru. Merits, Reparations and Costs. Judgment of April 6, 2006. Series C No. 147, para. 95, and Case of Gutiérrez and Family v. Argentina. supra, para. 119. 346 On this point, the Court considers it pertinent to recall that the use of circumstantial evidence, evidence and presumptions is legitimate, provided that the conclusions are consistent with the facts. Cf. Case of Velásquez Rodríguez v. Honduras, Merits, supra, paras. 130, and Case of the Supreme Court of Justice (Quintana Coello et al.) v. 68