of “conveying an impression of humanitarian aid that, in fact, contaminated the crime scene, by removing the body from the scene of the crime, knowing full well that it was a corpse, and not an injured person.” 288 In this regard, the Court finds that the action taken did not meet the basic requirements and was incomplete. 234. Furthermore, regarding the appraisals made of who fired the shots and of the ballistics comparison, the Court notes that, although an appraisal was made of the gunpowder residue and forensic and ballistic tests had been performed (supra paras. 80 and 81) on the weapon seized by police authorities and presumably used by Igmar Landaeta, no fingerprints were taken, 289 which could have corroborated the hypothesis of its use during the presumed confrontation with the police agents. Similarly, the Court has corroborated that the forensic tests and ballistic comparison appraisal were not performed on the weapons used by the police agents. These weapons were not confiscated from the police agents involved and there is no record in the case file of a ballistics comparison between the bullets that caused the death of Igmar Landaeta and those used by the authorities, and no fingerprints were taken from the weapons of the police agents. The Court considers that this is very significant, because ballistics evidence must be obtained every time a weapon has been used, 290 especially if an investigation involving State agents is being conducted in which the number of shots fired by the said agents must be established so as to help clarify whether the use of force by the police was necessary 291 and proportionate, and to exhaust all the lines of investigation in order to discover the truth. In this regard, the domestic laws in force at the time of the events established the need to identify the weapons used, their type and caliber. 292 235. In addition, with regard to the establishment of criminal responsibility, the Court notes that no appraisal was made to determine which shots were fired by each agent and no procedure was conducted to allow the eyewitnesses to identify the police agents. This would have been necessary so that these witnesses could identify, if possible, which of the agents fired the shots. 293 In addition, there is no record that the authorities performed other tests that could have provided further technical evidence to clarify the discrepancies between the different versions of what happened, such as an analysis of the vehicles, both the one that transported Igmar Landaeta to the medical center, as the supposed white vehicle behind which he allegedly hid during the presumed confrontation, according to the statements of some witnesses (supra paras. 63 and 65). Furthermore, no measure was taken to disprove the dispute regarding the way in which the second shot that caused the death of Igmar Landaeta was fired. 236. Based on the above, the Court considers that the lack of thoroughness in the investigation of the crime scene and in the autopsy, the shortcomings in the preservation 288 Testimony of expert witness José Pablo Baraybar of January 29, 2014 (merits file, folio 835). 289 Cf. Case of Garibaldi v. Brazil. Merits, reparations and costs. Judgment of September 23, 2009. Series C No. 203, para. 124 and Case of Veliz Franco et al., supra, para. 196 c). 290 Cf. ICRC, Guidelines for Investigating Deaths in Custody, supra, p. 13. 291 Cf. Case of Juan Humberto Sánchez, supra, paras. 111 and 112 and Case of J. v. Peru. Preliminary objection, merits, reparations and costs. Judgment of November 27, 2013. Series C No. 275, para. 330. 292 In this regard, article 126 of the Code of Criminal Procedure established that: “If the weapons or instruments used to commit the offense can be obtained, a drawing and a description shall be made which shall be added to the file of the proceedings and, in the case of firearms, their type and caliber shall be noted. When necessary to clarify the incident, the circumstances and the guilt of the perpetrators, a description of the topography of the site where the offense was perpetrated shall be added to the file.” 293 Article 181 of the Code of Criminal Procedure indicated specifically that: “[…] If the witnesses or victims do not know the name and other circumstances that would identify the suspect, an identification parade can be organized, so that they may identify the individual who they believe to be the offender […].” And, article 262 of the Code established the possibility of confronting witnesses if their statements were contradictory, as in this case, stipulating that: “The witnesses whose statements are contradictory shall be confronted with each other when one of the parties shall request this, or when the court orders this […].” 63