the scene of the crime must be thoroughly investigated; autopsies and analysis of human remains must be rigorously conducted by competent professionals and using the most appropriate procedures.119 113. Likewise, the Inter-American Court has held that in situations of violent deaths, investigators must, at the very least, photograph the scene and any other physical evidence, and the body as it was found and after it has been moved; gather and conserve the samples of blood, hair, fibers, threads and other clues; examine the area to look for footprints or any other trace that could be used as evidence, and prepare a detailed report with any observations regarding the scene, the measures taken by the investigators, and the assigned storage of all the evidence collected.120 For its part, the Minnesota Protocol establishes, among other obligations, that the area around the body must be closed off, and entry into it prohibited, except for the investigator and his team.121 114. Additionally, it has been established in the system of Inter-American jurisprudence that all technical evidence must be gathered as required to determine whether or not the use of force was strictly necessary and proportional, as well as to clarify discrepancies between opposing accounts of the circumstances surrounding the use of force.122 In the case of García Ibarra et al v. Ecuador, the Inter-American Court stressed the importance of expert witness technical reports to determine the plausibility of a hypothesis that a fatality from the use of force was “accidental,”123 which could be useful in the case before us. 115. After closely reviewing the investigations opened in the domestic arena, the Commission notes that, as of the first stages of the investigation several situations arose, which expose a lack of due diligence by the Mexican State. 116. Firstly, the Commission notices that the authority, who had control over the scene of the crime and of the evidence on the day of the death of Mirey Trueba and for a few days afterwards, before jurisdiction was ceded to the military system, was the Office of the Public Prosecutor. Based on the facts, it is evident that the Public Prosecutor’s Office conducted the first stage of the investigation, but the military forces themselves then assessed the evidence gathered at the scene and were authorized to request further evidence. 117. Secondly, based on the evidence made available to the IACHR, the investigation proved to not be exhaustive nor to exhibit the level of due diligence required to establish the legality of the use of deadly force and the consequences thereof in criminal law. The Commission notes that, as it is acknowledged in the judgment of the Military Supreme Court, the necessary technical ballistics tests were not conducted to determine the trajectory of the shots fired by Lieutenant Coronel Morales, nor were any other technical tests conducted to establish whether or not the account provided by the members of the military present at the time was true. On the contrary, in the aforementioned ruling, the military authority only noted that the “angle of the shot and the trajectory of the projectile were not possible to determine” without setting forth the reasons for it not being possible to do so, when technical evidence exists that may be able to shed light on these facts. Additionally, the Commission notes that even though there were differing versions of the facts between Mirey Trueba’s companions and the members of the military that stopped their car, no additional 119 United Nations Manual on the Effective Prevention and Investigation of Extra-legal, Arbitrary and Summary Executions. IA Court of HR. Case of González et al (“Cotton Field”) v. Mexico. Preliminary Objection, Merits, Reparations and Costs. Judgment of November 16, 2009. Series C No. 205, par. 301. 120 121 IA Court of HR. Case of González et al (“Cotton Field”) v. Mexico. Preliminary Objection, Merits, Reparations and Costs. Judgment of November 16, 2009. Series C No. 205, par. 301. 122 See IA Court of HR. Case of the Landaeta Mejías Brothers et al v. Venezuela. Preliminary Objections, Merits, Reparations and Costs. Judgment of August 27, 2014. Series C No. 281, pars. 234 – 236. 123 IA Court of HR. Case of García Ibarra et al v. Ecuador. Preliminary Objections, Merits, Reparations and Costs. Judgment of November 17, 2015. Series C No. 306. Par. 141. 22