Arbitrary and Summary Executions"140 is a useful tool to assess the steps taken by investigative authorities, especially in the first stages. This is the case because the above-mentioned instrument recapitulates the minimum, that is, the most basic steps that must be taken “to discover the truth about the events leading to the suspicious death of a victim."141 Thus, said Manual establishes that the state authorities that carry out an investigation must, inter alia: a) identify the victim; b) recover and preserve the evidentiary material related to the death; c) identify possible witnesses and obtain their statements with regard to the death that is being investigated; d) determine the cause, form, place, and time of death, as well as any procedure or practice that could have caused it, and e) distinguish between a natural death, an accidental death, suicide, and homicide. Besides, it is necessary to thoroughly investigate the crime scene, autopsies and competent professionals employing the most appropriate procedures must carefully practice analysis of the human remains.142 86. Likewise, the Commission observes that, as established by said document, due diligence in a forensic investigation of a death requires upholding the chain of custody of all the elements of forensic evidence.143 In that respect, the Inter-American Court has stated that: This consists in keeping a precise written record, complemented, as applicable, by photographs and other graphic elements, to document the history of the item of evidence as it passes through the hands of the different investigators responsible for the case. 144 87. First of all, the IACHR observes that, in the case file, there is no indication that the crime scene was protected as of the time of the incidents or that measures had been ordered to protect said evidence. Apart from the mention of some evidence gathered, there are no documentary or photographic records of the death of Mr. Pacheco León. Furthermore, the IACHR notes that a DGIC technical expert stated that, when he arrived at the crime scene several hours after Mr. Pacheco's death, " the crime scene had been tampere[d] with and that he saw shoe prints in blood stains.” Thus, the Commission noted that, from the very start, one of the minimum components cited above had been omitted, that is, a thorough examination of the crime scene. 88. Second, the Commission noted that, in the case file, Mr. Pacheco León's autopsy could not be found. The IACHR observes that the court itself assigned to the case requested the results of the autopsy and, in July 2004, the Prosecutor of the Attorney General's Office of the Department of Valle reported that "the conclusions from the autopsy (...) of Mr. Ángel León Pacheco could not be found in the court case file.” 89. Third, the IACHR observes that, according to statements made in December 2001 by an employee of the Ministry of Security and a medical examiner of the Judiciary, after the death of Ángel Pacheco, the chain of Mr. Pacheco's blood samples was not tracked nor were adequate steps taken to pack the evidence obtained. Furthermore, the Commission stresses that the State itself recognized that the blood samples obtained after the death of Mr. Pacheco had been destroyed “by accident." 140 United Nations Manual on the Effective Prevention and Investigation of Extra-Legal, Arbitrary and Summary Executions, adopted by the United Nations General Assembly in 1991. U.N. Document ST/CSDHA/12. 141 United Nations Manual on the Effective Prevention and Investigation of Extra-Legal, Arbitrary and Summary Executions, adopted by the United Nations General Assembly in 1991. U.N. Document ST/CSDHA/12, para. 9. 142 I/A Court H.R., Case of Servellón-García et al. v. Honduras. Judgment of September 21, 2006. Series C No. 152, para. 120. United Nations Manual on the Effective Prevention and Investigation of Extra-Legal, Arbitrary and Summary Executions and I/A Court H.R., Case of González et al. (“Cotton Field”) v. Mexico. Preliminary Objection, Merits, Reparations, and Costs. Judgment of November 16, 2009. Series C No. 205, para. 305. 143 144 I/A Court H.R., Case of González et al. (“Cotton Field”) v. Mexico. Preliminary Objection, Merits, Reparations, and Costs. Judgment of November 16, 2009. Series C No. 205, para. 305.