38 military justice system dismissed the case against all of the commandos involved in the events and in September of that year, ordered the case definitively closed. Parallel to this, in the ordinary jurisdiction, the Public Prosecutor’s Office filed charges in September 2006. The oral phase, which commenced in 2008, is still ongoing and has not delivered a verdict as of the date this report was adopted. Preservation of evidentiary material 174. In the first place, the IACHR recalls that in cases such as the one under study, in which a death has occurred at the hands of state agents, it is particularly important “that the competent authorities adopt all reasonable measures to guarantee the necessary probative material in order to carry out the 178 investigation.” In this regard, the Inter-American Court has specified that “the effective determination of the truth within the framework of the obligation to investigate the death of a person must be showed in the 179 first stages of the proceeding, with all diligence,” and must take into account the Manual on the 180 Effective Prevention and Investigation of Extra-legal Executions. In this sense, [t]he 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, perform autopsies and competent professionals employing the most appropriate procedures must carefully practice analysis of the 181 human remains. 175. The Commission observes that, according to the United Nations Manual on Extra-legal Executions, due diligence in a forensic medical investigation into a death requires maintaining a chain of 182 custody for each item of forensic evidence. On this point, the Inter-American Court has stated that This consists of 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. The chain of custody can extend beyond the trial, sentencing and conviction of the accused, given that old evidence, duly preserved, could help exonerate someone who has been convicted erroneously. The exception to the foregoing is the positively identified remains of victims, which can be returned to their families for 183 burial, on condition that they cannot be cremated and may be exhumed for new autopsies. 178 Inter-Am. Ct. H.R., Case of Zambrano Vélez et al v. Ecuador. Merits, Reparations and Costs. Judgment of July 4, 2007. Series C No. 166, para. 122. 179 Inter-Am. Ct. 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. 300; Inter-Am. Ct. H.R., Case of Servellón García et al v. Honduras. Judgment of September 21, 2006. Series C No. 152, para. 120; Inter-Am. Ct. H.R., Case of the Miguel Castro Castro Prison v. Peru. Judgment of November 25, 2006. Series C No. 160, para. 383 and Case of Zambrano Vélez et al v. Ecuador. Merits, Reparations and Costs. Judgment of July 4, 2007. Series C No. 166, para. 121 and United Nations Manual on the Effective Prevention and Investigation of Extra-legal, Arbitrary, and Summary Executions, E/ST/CSDHA/.12 (1991). 180 Inter-Am. Ct. H.R., Case of Servellón García et al v. Honduras. Judgment of September 21, 2006. Series C No. 152, para. 120; Inter-Am. Ct. H.R., Case of Montero Aranguren et al (Detention Center of Catia) v. Venezuela. Judgment of July 5, 2006. Series C No. 150, para. 140; Inter-Am. Ct. H.R., Case of Ximenes Lopes v. Brazil. Judgment of July 4, 2006. Series C No. 149, para. 179; Inter-Am. Ct. H.R., Case of the Ituango Massacres v. Colombia. Judgment of July 1, 2006. Series C No. 148, para. 298; and United Nations Manual on the Effective Prevention and Investigation of Extra-legal, Arbitrary, and Summary Executions, E/ST/CSDHA/.12 (1991). 181 Inter-Am. Ct. H.R., Case of Servellón García et al v. Honduras. Judgment of September 21, 2006. Series C No. 152, para. 120. 182 Manual on the Effective Prevention and Investigation of Extra-legal Executions, and Inter-Am. Ct. 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. 183 Inter-Am. Ct. 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.