are or may be involved.112 The duty to investigate is one of means, not results, that must be assumed by the State as its own legal duty and be undertaken in a serious manner and not as a mere formality preordained to be ineffective, or simply as a step taken by private interests that depends upon the initiative of the victim or his family or upon their offer of proof.113 The State’s obligation to investigate must be fulfilled diligently in order to avoid impunity and the recurrence of this type of event.114 88. 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.”115 In that regard, the State must show that it carried out an immediate, exhaustive and impartial investigation,116 and it must be aimed at exploring all the possible lines of inquiry.117 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.118 89. At the same time, Article 8(1) of the American Convention establishes as one of the elements of a fair trial that tribunals reach a decision on cases submitted for their consideration within a reasonable time. Pursuant to the provisions of that Article, the Commission will consider, in light of the specific circumstances of the case, the four elements that the organs of the inter-American system have taken into account: (i) the complexity of the case; (ii) the procedural activity of the interested party; (iii) the conduct of the judicial authorities; and (iv) the general effects on the legal situation of the person involved in the proceeding.119 The Inter-American Court has found that a prolonged delay may constitute, in itself, a violation of the right to a fair trial,120 and that, therefore, it is for the State to explain and prove why it has required more time than would be reasonable to deliver final judgment in a specific case.121 90. First, the Commission notes that although the State conducted internal proceedings relating to violations of human rights committed during the dictatorship of Luis García Meza and the events of July 17, 1980 in connection with the coup d’état, it was not until 13 years later that a first conviction was handed down by the Supreme Court of Justice in the trial to determine responsibilities initiated, moreover, only upon Bolivia's return to democracy. During all that time, the facts relating to the forced disappearance of Mr. Flores Bedregal were not investigated, despite the fact that from the day he disappeared his family members embarked on actions to search for his whereabouts. Thus 19 years elapsed before ordinary criminal proceedings began to establish additional liabilities, but they, too, failed to shed light on what really happened to Juan Carlos Flores Bedregal. The above implies that during that time the Bolivian State refrained from initiating an ex officio investigation into the facts, even though they were widely known and, as mentioned above, the family members had started searching immediately. The Commission considers that this fact in itself implies disregard for the State's duty to provide effective remedies to victims of human rights violations and their family members. I/A Court H.R. Case of Myrna Mack Chang v. Guatemala. Merits, Reparations, and Costs. Judgment of November 25, 2003. Series C No. 101, para. 156; and Case of the Afro-descendant communities displaced from the Cacarica River Basin (Operation Genesis) v. Colombia. Preliminary Objections, Merits, Reparations and Costs. Judgment of November 20, 2013. Series C No. 270, para. 371. 113 I/A Court H.R. Case of Velásquez Rodríguez v. Honduras. Merits. Judgment of July 29, 1988. Series C No. 1, para. 177; Case of Veliz Franco et al. v. Guatemala. Preliminary Objections. Merits, Reparations, and Costs. Judgment of May 19, 2014. Series C No. 277, para. 114 I/A Court H.R. Case of the Ituango Massacres v. Colombia. Judgment of July 1, 2006, Series C No. 148, par. 319; Case of Veliz Franco et al. v. Guatemala. Preliminary Objections, Merits, Reparations and Costs. Judgment of May 19, 2014. Series C No. 277, para. 183; and Case of Landaeta Mejías Brothers et al v. Venezuela, Preliminary Objections, Merits, Reparations and Costs. Judgment of August 27, 2014. Series C No. 281, para. 216 115 I/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, para. 131. 116 IACHR. IACHR, Report on Merits No. 55/97, Juan Carlos Abella et al. (Argentina), November 18, 1997, par. 412. 117 IACHR. IACHR, 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. 118 I/A Court H.R. The “Street Children” Case (Villagrán Morales et al.), par. Judgment of November 19, 1999. Series C No. 63, para. 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. 119 IACHR. Report No. 111/10, Case 12.539, Merits, Sebastián Claus Furlan and family, Argentina, October 21, 2010, par. 100. I/A Court H.R., Case of the Santo Domingo Massacre v. Colombia. Preliminary Objections, Merits and Reparations. Judgment of November 30, 2012. Series C No. 259, para. 164. 120 I/A Court H.R. Case of García Asto and Ramírez Rojas v. Peru. Judgment of November 25, 2005. Series C No. 137, para. 166; Case of Gómez Palomino v. Peru. Judgment of November 22, 2005. Series C No. 136, para. 85; Case of the Moiwana Community v. Suriname. Judgment of June 15, 2005. Series C No. 124, para. 160. 121 I/A Court H.R. Case of Ricardo Canese v. Paraguay, Judgment of August 31, 2004. Series C No. 111, para. 142. 112 24