141. In analyzing whether an investigation has been conducted with due diligence from the initial stages of proceedings, the Commission and the Inter-American Court have taken into consideration the United Nations Manual on the Effective Prevention and Investigation of Extra-legal, Arbitrary and Summary Executions. As the Court has specified: At a minimum, state authorities conducting an inquiry shall seek, inter alia: (a) to identify the victim; (b) to recover and preserve evidentiary material related to the death in order to aid in any potential prosecution of those responsible; (c) to identify possible witnesses and obtain statements from them concerning the death; (d) to determine the cause, manner, location and time of death, as well as any pattern or practice that may have brought about the death; and (e) to distinguish between natural death, accidental death, suicide and homicide. The Court further notes that: (a) the crime scene must be exhaustively investigated and (b) autopsies, as well as analyses of skeletal remains, must be rigorously performed by competent professionals, employing the most appropriate procedures.133 142. The Inter-American Court has also found that in situations in which a violent death has occurred, the 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 for all the evidence collected. 134 The obligations established by the Minnesota Protocol provide that, when investigating a crime scene, the area around the body must be closed off, and entry into it prohibited, except for the investigator and his team. 135 143. Furthermore, as regards due diligence in the course of the investigation, the Inter-American Court has determined that "each State act that composes the investigation proceeding, and the entire investigation in itself, should be oriented at a specific purpose: the determination of the truth and the investigation, finding, arrest, prosecution and, if applicable, punishment of those responsible for the events.”136 In that regard, the State must show that it carried out an immediate, exhaustive and impartial investigation,137 and it must be aimed at exploring all the possible lines of inquiry. 138 The State may be liable for a failure to order, practice or evaluate evidence that may have been essential for a proper clarification of the facts.139 144. In light of the foregoing standards, the Commission must determine if the State has conducted the investigations and criminal proceeding in accordance with those standards, in order to 133I/A Court H.R., Case of the Moiwana Community v. Suriname. Judgment of June 15, 2005. Series C No. 124, par. 149; I/A Court H.R., Case of the Miguel Castro-Castro Prison v. Peru. Judgment of November 25, 2006. Series C No. 160, par. 383. Citing the Manual on the Effective Prevention and Investigation of Extra-legal, Arbitrary and Summary Executions, Doc. E/ST/CSDHA/.12 (1991). The Commission has relied on United Nations documents to evaluate basic procedures to be carried out in such cases in previous matters. See IACHR. Report 10/95, (Manuel Stalin Bolaños Quiñonez). Case 10.580 Ecuador. September 12, 1995, par. 53. 134I/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, par. 301. The Court refers to the United Nations Manual on the Effective Prevention and Investigation of Extra-legal, Arbitrary and Summary Executions, U.N., Doc E/ST/CSDHA/.12 (1991). 135I/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, par. 301. 136I/A Court H.R., Case of Cantoral-Huamaní and García-Santa Cruz v. Peru. Preliminary Objection, Merits, Reparations and Costs. Judgment of July 10, 2007. Series C No. 167, par. 131. 137IACHR, Report on Merits No. 55/97, Juan Carlos Abella et al. (Argentina), November 18, 1997, par. 412. 138IACHR, Report No. 25/09, Merits (Sebastião Camargo Filho) Brazil, March 19, 2009, par. 109. See, too, IACHR, Access to Justice for Women Victims of Violence in the Americas, OEA/Ser. L/V/II. doc.68, January 20, 2007, para. 41. 139I/A Court H.R., The “Street Children” Case (Villagrán Morales et al.). Judgment of November 19, 1999. Series C No. 63, par. 230. See, too, IACHR, Access to Justice for Women Victims of Violence in the Americas, OEA/Ser. L/V/II. doc.68, January 20, 2007, para. 41.