71 true that both the aforementioned complaint and the habeas corpus petition filed referred to the detention and disappearance of persons in the same locality, on the same day, by members of the Peruvian Army. 270 235. On August 5, 1991, an appeal was filed before the Huancavelica Examining Magistrate against the ruling of July 22, 1991; however, it was not confirmed whether this appeal was resolved. 271 The Court recalls that Article 7(6) of the Convention requires a decision “without delay” and the Court has established violations in this regard for delays of 9, 21 and 31 days in the authorities’ responses after the habeas corpus petitions were filed. 272 For this reason, the lack of response to the appeal filed on August 5, 1991 before the Huancavelica Examining Magistrate’s Court is, in itself, a violation of this requirement. 236. Therefore, the Court finds that the writ of habeas corpus filed on July 18, 1991, before the Examining Magistrate’s Court of Huancavelica was not effective in determining the whereabouts of Elihoref Huamaní, so that the protection afforded by the writ was illusory. Consequently, in application of the iura novit curia principle, the Court considers that the State violated Article 7(6) of the American Convention to the detriment of Elihoref Huamaní and his next of kin (supra para. 84 and note 57). B.3. Obstructions in the investigations 237. This Court has indicated that the State authorities are obliged to refrain from acts that obstruct the progress of investigative processes. 273 238. In particular, the Court recalls that in order to ensure due process of law, the State must take all necessary measures to protect justice operators, investigators, witnesses and the family members of the victims from harassment and threats aimed at hindering the proceedings, preventing the elucidation of the facts and hiding those responsible. 274 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. 275 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 from being known. 276 239. In this case, first of all, the Court has already established that on July 11, 1991, the Army denied the detention of nine of the victims in response to a request for information from the Special Provincial Prosecutor for Crime Prevention of Huancavelica (supra para. 95); it also denied Cf. Complaint of Nicolás Hilario Morán, President of the Peasant Community of Santa Bárbara, of July 8, 1991, filed before the Special Prosecutor’s Office for Crime Prevention of Huancavelica (evidence file, folio 60), and writ of habeas corpus of July 18, 1991, filed by Alejandro Huamaní Robles before the Examining Magistrate’s Court of Huancavelica (evidence file, folio 82). 271 Cf. Appeal filed on August 5, 1991 against the order of the Examining Magistrate’s Court of Huancavelica of July 22, 1991 (evidence file, folio 88). It should be pointed out that in a note of February 5, 2015, the Court asked Peru for “information on the response given” to said appeal. The State responded in a letter of March 2 of the same year that “to date it has not been possible to obtain such information”, without this having been subsequently forwarded to the Court. 272 Cf. Case of Tibi v. Ecuador. Preliminary objections, merits, reparations and costs. Judgment of September 7, 2004. Series C No. 114, para. 134, and Case Chaparro Álvarez and Lapo Íñiguez v. Ecuador, supra, para. 135. 273 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 the Río Negro Massacres v. Guatemala, supra, para. 194. 274 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 Human Rights Defender et al. v. Guatemala, supra, para. 227. 275 Cf. Case of Kawas Fernández v. Honduras, supra, para. 106, and Case of the Human Rights Defender et al. v. Guatemala, supra, para. 227. 276 Cf. Case of the Dos Erres Massacre v. Guatemala, supra, para. 234, and Case of Human Rights Defender et al. v. Guatemala, supra, para. 227. 270