145. Moreover, the investigation must be conducted exhaustively and diligently. This means, on the one hand, that the State has the obligation to carry out all those inquiries that are necessary to ensure that the victims know the truth of all the events that occurred and that those who are involved in the crimes are punished, whether they have acted as material authors, participants, instigators, or accessories110. Likewise, the InterAmerican Court has established that the judge, as the competent authority to direct the process, has the duty to prosecute it in such a way as to avoid “that undue delays and obstructions lead to impunity, thus frustrating the due judicial protection of human rights”111. Indeed, as the Inter-American Court has indicated: [I]n complex cases, such as the present one, the obligation to investigate entails the duty to direct the efforts of the state apparatus to unravel the structures that allowed these violations, their causes, their beneficiaries, and their consequences, for which an investigation can only be effective if carried out from a comprehensive point of view of the events, which takes into account the background and the context in which they occurred, and seeks to unveil the participation structures112. 146. Adequate compliance with the principle of independence and impartiality, for its part, demands that the State guarantee that the bodies in charge of intervening in the judicial process - whether during the investigatory phase or in the trial itself - approach the matter with as much objectivity as possible. This implies, in essence, that the intervening judges must be free from personal prejudices and must offer sufficient guarantees so that the parties to the process do not harbor justified doubts regarding their impartiality113. 147. Regarding the manner in which an investigation is conducted, the Inter-American Court has indicated that it is not appropriate to replace the domestic jurisdiction by establishing the specific investigation and prosecution modalities in a specific case in order to obtain a better or more effective result, but rather to verify whether or not the steps actually taken at the domestic level violated the State's international obligations 114. In cases where the facts refer to the violent death of a person, the Court has indicated that the investigation initiated must be conducted in such a way that it could guarantee due analysis of the hypotheses on the author that arose as a result of the investigation 115 . Likewise, it is necessary that the investigation be conducted avoiding omissions in the collection of evidence and in following the logical lines of investigation 116. 148. In this regard, the State must demonstrate that it has carried out an immediate, exhaustive, serious, and impartial investigation117, which must be aimed at exploring all possible lines of investigation that allow the identification of the perpetrators of the crime, for their subsequent prosecution and sanction118. The State may be responsible for not "ordering, practicing, or evaluating evidence" that may be essential for the proper clarification of the facts119. 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. 217; I/A Court H.R., Case of Serrano Cruz Sisters v. El Salvador. Merits, Reparations and Costs. Judgment of March 1, 2005. Series C No. 120, para. 83; I/A Court H.R., Case of Coc Max et al. (Massacre of Xamán) v. Guatemala. Merits, Reparations and Costs. Judgment of August 22, 2018. Series C No. 356, para. 81. 111 I/A Court H.R., Case of Bulacio v. Argentina. Merits, Reparations and Costs. Judgment of September 18, 2003. Series C No. 100, paras. 114 to 116; I/A Court H.R., Case of García Ibarra et al. v. Ecuador. Preliminary Objections, Merits, Reparations and Costs. Judgment of November 17, 2015. Series C No. 306, para. 132. 112 I/A Court H.R., Case of Rodríguez Vera et al. (The Disappeared from the Palace of Justice) v. Colombia. Preliminary Objections, Merits, Reparations and Costs. Judgment of November 14, 2014. Series C No. 287, para. 500. 113 I/A Court H.R., Case of Herrera Ulloa v. Costa Rica. Preliminary Objections, Merits, Reparations and Costs. Judgment of July 2, 2004. Series C No. 107, paras 169 to 171. 114 I/A Court H.R., Case of Nogueira de Carvalho et al. v. Brazil. Preliminary Objections and Merits. Judgment of November 28, 2006. Series C No. 161, para. 80. 115 I/A Court H.R., Case of Kawas Fernández v. Honduras. Merits, Reparations and Costs. Judgment of April 3, 2009. Series C No. 196, para.112. 116 I/A Court H.R., Case of Tiu Tojín v. Guatemala. Merits, Reparations and Costs. Judgment of November 26, 2008. Series C No. 190, para. 77. 117 IACHR, Merits Report, No. 55/97, Juan Carlos Abella and Others (Argentina), November 18, 1997, para. 412. 118 IACHR, Report No. 25/09 Merits. Sebastião Camargo Filho. Brazil, March 19, 2009, para. 109. See also, 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 I/A Court H.R., Case of the “Street Children” (Villagrán Morales et al.) v. Guatemala. Reparations and Costs. Judgment of May 26, 2001. Series C No. 77, para. 230. See also, IACHR, Access to Justice for Women Victims of Violence in the Americas, OEA / Ser. L / V / II. doc.68, January 20, 2007, para. 41. 110 29