observance or the violation of the rights of those subject to the jurisdiction of a specific State.177 For its part, the Office of the United Nations High Commissioner for Human Rights has stated that failure to investigate and punish those responsible for violations committed against human rights defenders "constitutes the factor that most increases the risk to defenders, because it leaves them in a situation of defenselessness and vulnerability.”178 80. The special and heightened obligations to investigate where human rights defenders are concerned, are wholly applicable in this case as there are clear indications that a link existed between Mr. García Valle’s murder and María Luisa Acosta’s work in defense of rights. 81. Taking into account the established facts and the arguments of the parties, the Commission will pronounce, first, on the duty to investigate with due diligence; second, on the denial of the appeal against the dismissal of the possible masterminds; and, third, on the guarantee of a reasonable time. 1. The duty to investigate with due diligence 82. As to the substance of the duty to investigate with due diligence, the Inter-American Court has held that this duty entails that the investigation be undertaken utilizing all the legal means available and should be oriented toward the determination of the truth.179 The Court has also held that the State may be liable for a failure to order, practice or evaluate evidence that may have been essential for a proper clarification of the facts.180 Thus, the IACHR recalls that the obligation to investigate and punish every act that entails a violation of the rights protected by the Convention requires that not only the direct perpetrators of human rights violations be identified, but also the masterminds.181 In that regard, the authorities should also adopt all reasonable measures to guarantee the necessary probative material in order to carry out the investigation.182 83. The commission will analyze whether the state fulfilled its duty to investigate with due diligence taking into account the following: (i) the lack of investigation into the motive for the murder; and (ii) the lack of investigation of the third perpetrator. 1.1 The lack of investigation into the motive for the murder 84. The Inter-American Court has held that it is not the task of the organs of the inter-American system to "analyze the hypothesis about perpetrators prepared during the investigation of the events of the ... case and determine individual responsibility, whose definition corresponds to domestic criminal tribunals, but rather evaluate the acts and omission of State agents, pursuant to the evidence submitted by the 177 I/A Court H.R., Case of Valle Jaramillo et al. v. Colombia. Merits, Reparations and Costs. Judgment of November 27, 2008. IACHR, Annual Report 2011, OEA/Ser.L/V/II., Doc. 192, par. 96. Cf. Case of Nogueira de Carvalho et al. v. Brazil. Preliminary Exceptions and Merits. Judgment of November 28, 2006. Series C No. 161, par. 76. 178OHCHR. Defender los derechos humanos: entre el compromiso y el riesgo [Defending human rights: between the commitment and the risk] Executive Summary, para. 7. http://www.hchr.org.mx/documentos/libros/informepdf.pdf 179I/A Court H.R., Case of García-Prieto et al. Preliminary Objection, Merits, Reparations and Costs. Judgment of November 20, 2007, Series C No. Series C No. 168. par. 101. 180I/A Court H.R., The “Street Children” Case (Villagrán Morales et al.) v. Guatemala. Judgment of November 19, 1999. Series C No. 63, par. 230. See also IACHR, Report No. 56/12, Merits (Florentín Gudiel Ramos, Makrina Gudiel Álvarez et al.), Guatemala, March 21, 2012, par. 126; IACHR, Access to Justice for Women Victims of Violence in the Americas, OEA/Ser. L/V/II. doc.68, January 20, 2007, par. 41. 181IACHR, Report No. 56/12, Merits (Florentín Gudiel Ramos, Makrina Gudiel Álvarez et al.), Guatemala, March 21, 2012, par. 110; IACHR, Report 100/11, Merits (Carlos Antonio Luna López et al.), Honduras, July 22, 2011, par. 188. See, also, IACHR, Report on the Situation of Human Rights Defenders in the Americas, OEA/Ser.L/V/II.124. Doc. 5 rev.1, March 7, 2006, par. 109. 182I/A Court H.R., Case of Zambrano-Vélez et al. v. Ecuador. Merits, Reparations and Costs. Judgment of July 4, 2007. Series C No. 166, par. 122.