98. 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 punished, but also the instigators and those who aid and abet such acts.108 99. In light of the above, analysis is needed to ascertain whether the manner in which the investigation into Mr. Gómez's death was conducted constituted a violation of the obligation to guarantee the substantive rights reviewed in the foregoing section and of the obligations derived from the rights upheld in Articles 8.1 and 25.1 of the American Convention. To that end, the IACHR will proceed to review the following aspects: irregularities in the investigation after the finding of Alejandro Gómez's body and subsequent acts carried out by State agents; ii) lack of due diligence in subsequent stages of the investigation; and iii) the matter of reasonable time allowed. 1. Irregularities in the investigation following the finding of Alejandro Gómez's body and subsequent acts by State agents. 100. The Court has established that efficient and fervent determination of the truth in connection with the obligation to investigate a death must be evident as of the very first procedures.109 In this area, with respect to handling of the crime scene, the identification and handling of the victim's corpse, the autopsy, and maintenance of the chain of custody of all items of forensic evidence, and bearing in mind the United Nations Manual on the Effective Prevention and Investigation of Extra-legal, Arbitrary and Summary Executions (Protocol of Minnesota), States must take minimal and indispensable steps to ensure the preservation of all elements of proof and evidence that may contribute to the success of the investigation.110 101. The Court and the Commission have specified that the State authorities who conduct an investigation of this type must try, at the very least, inter alia: (i) to identify the victim; (ii) to recover and preserve the probative material related to the death in order to assist in any potential criminal investigation of those responsible; (iii) to identify possible witnesses and obtain their statements in relation to the death under investigation; (iv) to determine the cause, manner, place and time of death, as well as any pattern or practice that could have caused the death, and (v) to distinguish between natural death, accidental death, suicide and homicide. In addition, the crime scene must be exhaustively investigated and autopsies, as well as analyses of skeletal remains, must be rigorously performed by competent professionals, employing the most appropriate procedures.111 102. The Commission underscores that correct handling of the crime scene is a starting point for the investigation and therefore vital for throwing light on the nature, circumstances, and characteristics of the crime and the participant in the crime.112 In its jurisprudence, the Court has held that a State may be liable for a failure to "order, practice or evaluate evidence that may have been vital for a proper clarification of homicides."113 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. I/A Court HR. Case of the Gómez Paquiyauri Brothers v. Peru. Merits, Reparations, and Costs. Judgment of July 8, 2004. Series C No. 110, par. 146; Case of Myrna Mack Chang v. Guatemala. Merits, Reparations, and Costs. Judgment of November 25, 2003. Series C No. 101, par. 275; and Case of Juan Humberto Sánchez v. Honduras. Preliminary Objection, Merits, Reparations and Costs. Judgment of June 7, 2003. Series C No. 99, par. 186; Case of the Constitutional Court v. Peru. Competence. Judgment of September 24, 1999. Series C No. 55, par. 123. 108 109 IACHR Report No. 49/15, Case 12.585, Merits, Ángel Pacheco León and Family, Honduras, July 28, 2015, par. 82. I/A Court HR. Case of Human Rights Defender et al. v. Guatemala. Preliminary Objections, Merits, Reparations, and Costs. Judgment of August 28, 2014. Series C No. 283, par. 204. 110 111 Cf. IACHR. Report No. 10/95. Case 10.580. Ecuador. September 12, 1995. par. 32; I/A Court H.R. Case of Juan Humberto Sánchez v. Honduras. Preliminary Objection, Merits, Reparations and Costs. Judgment of June 7, 2003. Series C No. 99, par. 127. 112 IACHR Report No. 49/15, Case 12.585, Merits, Ángel Pacheco León and Family, Honduras, July 28, 2015, par. 87. I/A Court HR. Case of Veliz Franco et al. v. Guatemala. Preliminary Objections, Merits, Reparations, and Costs. Judgment of May 19, 2014. Series C No. 277, par. 195. 113 18