156. Regarding the duty to initiate ex officio the investigation, the system’s bodies have constantly pointed out that “whenever there are reasonable grounds to suspect that a person has been subjected to enforced disappearance, a criminal investigation must be opened.” This obligation is regardless of whether or not a complaint has been filed, because, in cases of forced disappearance, international law and the general obligation of guarantee impose the obligation to investigate the case ex officio, immediately and in a genuine, impartial, and effective manner; hence, it does not depend on the procedural initiative of the victim or his next of kin or on the provision of evidence by private individuals.166 The same actions are required when authorities are apprised of alleged incidents of torture.167 157. Regarding the duty to order and bring forward the relevant evidence in line with the duty of due diligence, the Commission and the Court have specified that, in cases of human rights violations, the investigation must be aimed at exploring all possible lines of investigation, which would make it possible to identify the perpetrators of said violation. 168 The Court has also established that, in complex cases, “the obligation to investigate entails the duty to use the efforts of the State apparatus to clarify the structure that permitted these violations, the causes, the beneficiaries, and the consequences; hence an investigation can only be effective if it is conducted based on a comprehensive vision of the facts that takes into account the background and the context in which they occurred and that seeks to reveal the structures of participation.”169 158. Furthermore, the Court has pointed out that states must remove all obstacles and mechanisms of fact and law that uphold the impunity, as well as use all measures within their reach to pursue prosecution. 170 Regarding the obstacles represented by Laws No. 23.492 and No. 23.521, as well as Decree No. 1002/98, for the investigation and punishment of human rights violations perpetrated during Argentina’s dictatorship, the Inter-American Commission concluded in 1992 that they were incompatible with Article XVIII of the American Declaration and Articles 8 and 25 of the American Convention, in connection with its Article 1.1. This was because the legal consequence of their passage was that they “denied the victims their right to obtain a judicial investigation in a court of criminal law to determine those responsible for the crimes committed and punish them accordingly.”171 159. Likewise, since the Case of Barrios Altos, the Inter-American Court has pointed out that:172 all amnesty provisions, provisions on prescription and the establishment of measures designed to eliminate responsibility are inadmissible, because they are intended to prevent the investigation and punishment of those responsible for serious human rights violations such as torture, extrajudicial, summary or arbitrary execution and forced disappearance, all of them prohibited because they violate non-derogable rights recognized by international human rights law. 2. Analysis of the case 160. Below, the Commission shall examine the actions carried out by the state in connection with the criminal investigation of the crimes of forced disappearance and torture against the Julien-Grisonas family, namely: (i) the existence of obstacles in the investigation while Laws 23.492 and 23.521 were in force; (ii) the I/A Court H.R. Case of Osorio Rivera and family members v. Peru. Preliminary Objections, Merits, Reparations, and Costs. Judgment of November 26, 2013. Series C No. 274, para. 178. 167 I/A Court H.R. Case of Bayarri v. Argentina. Preliminary Objection, Merits, Reparations, and Costs. Judgment of October 30, 2008. Series C No. 187, para. 92. 168 IACHR. Report No. 25/09. Merits. Sebastião Camargo Filho. Brazil, March 19, 2009, para. 109; I/A Court H.R. Case of J. v. Peru. Preliminary Objection, Merits, Reparations, and Costs. Judgment of November 27, 2013. Series C No. 275, para. 344. 169 I/A Court H.R. Case of Rodríguez Vera et al. (the Disappeared from Palace of Justice) vs. Colombia. Preliminary Objections, Merits, Reparations, and Costs. Judgment of November 14, 2014. Series C No. 287, para. 500. 170 I/A Court H.R, Case of Carpio Nicolle et al. v. Guatemala. Merits, Reparations, and Costs. Judgment of November 22, 2004. Series C No. 117, para. 134. 171 IACHR. Report No 28/92. Cases 10.147, 10.181, 10.240, 10.262, 10.309 y 10.311. Argentina. October 2, 1992, para. 50. 172 I/A Court H.R. Case of Barrios Altos v. Peru. Judgment of March 14, 2001. Series C No. 75, para. 41. 166