124. Having said that, the obligation to investigate is an obligation as to means, rather than as to results, a duty to be assumed by the State as a judicial obligation itself and not as a mere formality preordained to be ineffective.194 In this sense, the investigation should be undertaken with due diligence, effectively, seriously, impartially,195and within a reasonable period of time.196 125. Following, the Commission analyzes if in the instant case the State of Guatemala carried out an independent, impartial and diligent investigation within a reasonable time. 3.1. Duty to carry out an independent and impartial investigation 126. The case law of the Inter-American system has consistently stated that special jurisdictions, such as the military criminal justice system, should have a restricted and exceptional scope and be designed to protect special juridical interests associated with the entity itself. Thus, the Court has had the opportunity to analyze the structure and composition of special tribunals, such as military courts, in the light of the United Nations Basic Principles on the Independence of the Judiciary. A number of relevant factors are: (i) that they are made up of active-duty officers who are hierarchically subordinate to higher-ranked officers through the chain of command; (ii) that their designation does not depend on their professional skills and qualifications to exercise judicial functions; and (iii) that they do not have sufficient guarantees that they will not be removed. This has led to the conclusion that such tribunals lack the necessary independence and impartiality to take cognizance of human rights violations.197 127. The Commission and the Court have referred to the incompatibility with the American Convention of the use of military criminal tribunals in cases involving human rights violations, noting that the fact that the very same military forces are those “charged with prosecuting their peers for executing civilians” is problematic for the guarantee of independence and impartiality.198 Accordingly, the Court has found that, as a special jurisdiction, military courts should only try active military personnel “for committing crimes or misdemeanors that, due to their nature, harm the juridical interests of the military system.”199 Additionally, in light of the aforementioned standards in the European human rights system regarding this type of case, the European Court has stressed the need for the persons in charge of the investigation be different from those who are implicated in the crimes200. The European Court indicated that such guarantee lies in the assurance of hierarchical, institutional and functional independence in the authority that is the trier of fact.201 128. In the instant case, the Commission notes that in the wake of the events, the investigation was initially conducted in the military criminal jurisdiction. The Commission finds that the investigation was 194 I/A Court H.R., Velásquez Rodríguez Case v. Honduras. Merits, Judgment of July 29, 1988. Series C No. 4, par. 177; 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. 195 I/A Court H.R., Case of García-Prieto et al. v. El Salvador. Preliminary Objection, Merits, Reparations, and Costs. Judgment of November 20, 2007. Series C No. 168, par. 101; Case of the Gómez Paquiyauri Brothers v. Peru. Judgment of July 8, 2004. Series C No. 110, par. 146; 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. 130. 196 I/A Court H.R., Case of Bulacio v. Argentina. Judgment of September 18, 2003. Series C No. 100, par. 114; I/A Court H.R., Case of the Rochela Massacre v. Colombia. Merits, Reparations and Costs. Judgment of May 11, 2007. Series C No. 163, par. 146; I/A Court H.R., Case of the Miguel Castro-Castro Prison v. Peru. Judgment of November 25, 2006. Series C No. 160, par. 382. 197 I/A Court H.R., Case of Palamara Iribarne v. Chile. Merits, Reparations and Costs. Judgment of November 22, 2005, Series C No. 135, par. 155 and 156. 198 I/A Court H.R., Case of Las Palmeras v. Colombia. Merits, Judgment of December 6, 2001. Series C No. 90, par. 53. See, also, IACHR, Report No. 10/95, Case 10.580, Manuel Stalin Bolaños, Ecuador, September 12, 1995. 199 I/A Court H.R., Case of Radilla Pacheco v. Mexico. Preliminary Objections, Merits, Reparations, and Costs. Judgment of November 23, 2009. Series C No. 209, par. 272. 200 ECHR, Sergey Shevchenko v. Ukraine. Communication No. 32478/02. Judgment of April 4, 2006, para. 64. 201 ECHR, Sergey Shevchenko v. Ukraine. Communication No. 32478/02. Judgment of April 4, 2006, para. 64. 28