Military Justice] compatible with international standards of the field and of the American Convention on Human Rights.”112 Said order was reiterated in three subsequent cases involving Mexico, in which military criminal jurisdiction was used, based on Article 57.II.a of the Code of Military Justice.113 In keeping with the foregoing recommendation, on June 13, 2014, the reform of said provision was published in the Official Gazette establishing that human rights violations committed against civilians may not be heard by military justice. 109. Because the case was heard by the military courts, when the above cited legal framework was in force, which prevented an independent investigation and proceeding from taking place, the Commission finds that the State breached its obligation of domestic legal effects as provided under Article 2 of the Convention. 110. Based on the preceding considerations, the Commission concludes that by leaving in place the legal framework that allowed for the application of military justice to the instant case, the Mexican State violated the right to a fair trial and judicial protection, specifically the right to have a competent, independent and impartial authority, pursuant to Article 8.1 and 25.1 of the American Convention in connection with Article 1.1 and 2 of this same instrument, to the detriment of Mirey Trueba’s next of kin. 2. Due diligence in the investigations 111. The IACHR has stressed that the State must prove that it has conducted an immediate, exhaustive, serious and impartial investigation,114 which must be aimed at exploring all possible lines of inquiry.115 For this reason, the State can be held accountable for “failing to order, practice or evaluate evidence” that may be critical to solving a case.116 For its part, the European Court of Human Rights has held that in cases where there is evidence of homicide caused by State agents, “an investigation will not be effective unless all the evidence is properly analyzed and the conclusions are consistent and reasoned.”117 112. Both the IACHR and the Inter-American Court have specified that in order to fulfill the obligation to investigate the death of a person, States are obligated to act, from the first stages of the proceeding, with all diligence.118 For purposes of analyzing the due diligence with which an investigation is conducted, from the first stages of the proceedings, the Commission and the Court have taken into consideration the United Nations Manual on the Effective Prevention and Investigation of Extra-legal, Arbitrary and Summary Executions, which reads as follows: The state authorities conducting the inquiry shall, at a minimum, seek: a) to identify the victim; b) to recover and preserve evidentiary material related to the death 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. Additionally, 112 IA Court of HR. Case of Radilla Pacheco v. Mexico. Preliminary Objections, Merits, Reparations and Costs. Judgment of November 23, 2009. Series C No. 209, tenth operative paragraph and paragraphs. 337 to 342. 113 IA Court of HR. Case of Fernández Ortega et al. v. Mexico, Preliminary Objection, Merits, Reparations and Costs. Judgment of August 30, 2010 Series C No. 215, par. 178-179; and Case of Rosendo Cantú et al v. Mexico, Preliminary Objection, Merits, Reparations and Costs. Judgment of August 31, 2010 Series C No. 216, par. 162-163. 114 IACHR, Case 11.137, Report No. 55/97, Merits, Juan Carlos Abella, Argentina, November 18, 1997, par. 412. 115 IACHR, Case 12.310, Report No. 25/09, Merits, Sebastião Camargo Filho, Brazil, March 19, 2009, par. 109. 116 IACHR, Access to Justice for Women Victims of Violence in the Americas, OEA/Ser. L/V/II. doc. 68, January 20, 2007, par. 41. 117 ECHR, Masneva v. Ukraine, Application no. 5952/07, 20 December 2011, § 49. 118 IACHR, Case 12.251, Report No. 85/13, Admissibility and Merits, Vereda La Esperanza, Colombia, November 4, 2013, par. 248. Also, see: IA Court of HR. Case of Zambrano Vélez et al v. Ecuador. Merits, Reparations and Costs. Judgment of July 4, 2007. Series C No. 166, par. 121. 21