the autopsy. The Court has also pointed out that due diligence in the investigation of a death requires preserving the chain of custody of every element of forensic evidence. 760 490. In this case, it has been proved, and the State has acknowledged, that the scene of the events was altered, and that serious errors were committed in the removal of the corpses, which was controlled by military criminal investigation judges, 761 and in which personnel who did not have the necessary training participated (supra para. 146). In addition, it has been proved that the initial procedures were not carried out in a methodical, technical or professional manner: measures were not taken to safeguard and preserve the scene appropriately; some corpses were moved from the place where death had occurred; the remains were not collected and stored individually so that, in some cases, the remains of more than one person were combined, thus contaminating the evidence; 762 some corpses were undressed; some were “carefully washed” prior to the respective autopsy; also, several days later, when the building was being cleaned, some remains were found that had not been registered or removed by the authorities, and even some of these remains were “disposed of” (supra paras. 145 to 150). Owing to these irregularities, in some case, the records of the removal of the corpses and the autopsies did not contain exact information or, as in the case of Mr. Urán Rojas, did not contain all the necessary information. Furthermore, “numerous errors” were committed in the autopsies; 763 identification methods were used that, although valid, had a greater margin of error, and that did not take into account the irregularities committed previously during the removal of the corpses (supra paras. 151 to 154). Lastly, in an extremely questionable decision, 38 corpses were buried in a mass grave, including some that had been identified, supposedly to avoid a new attack by the M-19 (supra para. 155). The Court finds it particularly egregious that, when carrying out this burial, the corpses were not separated, individualized or marked in some way so as to facilitate their subsequent identification or crosschecking against the records of the removal of corpses and the autopsies that were performed. para. 204. 760 United Nations Manual on the Effective Prevention and Investigation of Extra-legal, Arbitrary and Summary Executions (Minnesota Protocol), UN Doc. E/ST/CSDHA/.12 (1991), and 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 and 310. 761 In this regard, the Superior Court of Bogota considered that “within the judicial structure nothing moved without the express order of the security forces”; the work was only assigned to three military criminal investigation [judges] attached to the Bogota Police Department, a situation that the Chamber considers indicates the intention of concealing evidence that could be used to clarify the facts fully, or of making such evidence disappear’; “a direct intervention by the National Army in the procedures to inspect or to remove the corpses [has not been proved], but rather the presence of soldiers transporting corpses, observed by members of the judicial police.” Judgment of the Criminal Chamber of the Superior Court of Bogota of January 30, 2012 (evidence file, folios 22996 and 22998). 762 According to the testimony of the Forensic Pathologist of the Institute of Forensic Medicine at the time, he “was not present for the removal of the corpses because that task was not performed by the Institute of Forensic Medicine; however, [he] received corpses that were incorrectly labeled as regards the sex or the number as follows: the corpses arrived in plastic bags with a number that had been placed by the officials who carried out the removal of the corpse and sometimes, when undoing the bags in order to perform the autopsy, remains were found that corresponded to different corpses.” Testimony provided by Dimas Denis Contreras Villa on February 5, 1988, before the 30th Itinerant Criminal Investigation Court of Bogota (evidence file, folios 30889 and 30890). 763 In this regard, Carlos Bacigalupo indicated that “[i]t has been established that the actions of the National Institute of Forensic Medicine in the identification of the corpses that arrived from the Palace were deficient.” He added that “the identifications that were made […] did not comply with the basic international standards at the time […] and, consequently, neither did the return of the remains to the next of kin […], a responsibility that also fell to the military criminal investigation judge who ordered that the bodies be sent to the mass grave.” Written notes by Carlos Bacigalupo (evidence file, folios 36315, 36328, 36329, 36446, and 36455). Similarly, Máximo Duque declared that “the circumstances of the facts that occurred in a context of a massive disaster, the forensic and criminalistics technology available at the time (1985), and the inconsistencies that can be detected nowadays in the identification of several cases, signify that there were technical limitations in the procedures and that it is very probable that errors occurred in the identifications, and confusion in the return of the corpses.” Written report of Máximo Duque Piedrahíta (file of affidavits, folio 36446). 171