46 adverse effect of the duration of the proceedings on the judicial situation of the person involved in it must be taken into account; bearing in mind, among other elements the matter in dispute. If the passage of time has a relevant impact on the judicial situation of the individual, the proceedings should be carried out more promptly so that the case is decided as soon as possible. 156. Although the domestic criminal proceedings in this case include three alleged victims, one of aggravated murder and two of simple kidnapping, the Court observes that the investigation has been complex as regards the arrest of the accused (who were even tried in absentia owing to the clandestine nature of paramilitary groups), and also the identification of all the perpetrators. The Court has referred in its case law to the difficulties faced by a State to respond properly and adequately to its international commitments when it must prosecute unlawful acts by members of groups that have taken up arms.114 Nevertheless, the Court reiterates that the domestic situation of a State Party to the American Convention does not liberate it from its obligations under this treaty.115 In this regard, and even though two of those responsible in this case who belong to paramilitary groups have been convicted, the Court finds that the complexity of the matter under investigation in the domestic jurisdiction does not, in itself, justify the fact that criminal proceedings are still open 10 years after the event. 157. Regarding the procedural activity of the interested party, it should be recalled that the instant case involves, inter alia, an extrajudicial execution and that, consequently, the State has the obligation to initiate, ex officio and without delay, a serious, impartial, and effective investigation.116 Consequently, the effective search for the truth in this case corresponds to the State and does not depend on the procedural initiative of the victim or of his next of kin, or on their contribution of probative elements.117 Additionally, nothing in the file before the Court shows that the alleged victims delayed or obstructed the judicial proceedings. 158. With regard to the conduct of the judicial authorities, the Court observes that the Colombian State opened the formal criminal investigation into the facts on July 8, 1998, and that this investigation culminated in a judgment of the Third Criminal Court of the Medellín Specialized Circuit on March 15, 2001, convicting two civilians as perpetrators of the murder of Jesús Valle Jaramillo and another as responsible for the offense of forming part of a paramilitary group, and acquitting seven of the ten accused of all charges (supra para. 149). Therefore, since only slightly more than three years elapsed between the occurrence of the facts, their investigation, the application of the norms in force, and the subsequent determination of two perpetrators in the case, the Court considers that, as regards these proceedings specifically, the measures taken by the Colombian State’s prosecutors and judiciary were in keeping with criteria of diligence and reasonableness. 114 Cf. Case of the “Mapiripán Massacre”, supra note 21, para. 238; Case of the Ituango Massacres, supra note 21, para. 300, and Case of the Pueblo Bello Massacre, supra note 30, para. 146 115 Cf. Case of Bámaca Velásquez, supra note 80, para. 207; Case of the Ituango Massacres, supra note 21, para. 300, and Case of the Pueblo Bello Massacre, supra note 30, para. 146. 116 Cf. Juan Humberto Sánchez v. Honduras. Preliminary objections, merits, reparations and costs. Judgment of June 7, 2003. Series C No. 99, para. 112; Case of Heliodoro Portugal, supra note 13, para. 115, and Case of García Prieto et al., supra note 58, para. 101. 117 Cf. Case of Velásquez Rodríguez, supra note 20, para. 177; Case of Heliodoro Portugal, supra note 13, para. 145, and Case of Albán Cornejo et al., supra note 5, para. 62.