- 75 - (d) Remove all the obstacles that prevent the adequate investigation of the facts in the respective proceedings so as to avoid a repetition of acts and circumstances such as those of the instant case.314 In this regard, the State may not apply amnesty laws or argue prescription, non-retroactivity of the criminal law, res judicata, the principle of ne bis in idem, or any other similar mechanism that excludes responsibility, in order to exempt itself from this obligation;315 (e) Ensure that those who take part in the investigation, including victims, witnesses and administrators of justice, are provided with the necessary guarantees for their safety. (f) When investigating the interaction between the illegal group and State agents and civilian authorities, conduct with special diligence the exhaustive investigation of all individuals with connections to State institutions and the members of paramilitary groups who could be involved. Hence, the application of the principle of the most favorable law316 or the granting of any other administrative or penal benefit should not create any kind of obstacle to due diligence in the investigation of crimes associated with the perpetration of serious human rights violations, and (g) Ensure that the paramilitaries who have been extradited are accessible to the competent authorities and continue cooperating with the proceedings being conducted in Colombia. The State should also ensure that the proceedings abroad do not obstruct or interfere with the investigations into the serious violations that occurred in the instant case, or reduce the rights recognized to the victims in this judgment,317 using mechanisms that enable those extradited to collaborate with the investigations conducted in Colombia and, if appropriate, the participation of the victims in the measures taken abroad. 314 Cf. Case of La Cantuta v. Peru, supra note 180, para. 226; Case of the Dos Erres Massacre v. Guatemala, supra note 57, para. 240, and Case of Anzualdo Castro v. Peru, supra note 36, para. 182. 315 Cf. Barrios Altos v. Peru. Merits. Judgment of March 14, 2001. Series C No. 75, paras. 41 to 44; Case of the Dos Erres Massacre v. Guatemala, supra note 57, para. 233, and Case of Anzualdo Castro v. Peru, supra note 36, para. 182. 316 Regarding the possible application of Law 1312 of 2009, amending Law 906 of 2004, in the future, in relation to the principle of the most favorable law, the Court notes that it includes the possibility of applying this principle to those demobilized from a paramilitary group and empowers the office of the Prosecutor General of the Nation to suspend, interrupt or waive criminal prosecution in these cases. In particular, the Law indicates that, in order to accede to this benefit, the person demobilized must have demonstrated unequivocally his willingness to reincorporate society; he must not have applied to be included under the Justice and Peace Law procedure, and there must be no investigations against him for crimes committed before or after his demobilization, with the exception of belonging to the criminal organization, illegal use of uniforms and insignias, and illegally bearing arms and ammunition. Although this law establishes that “for the application of this provision, the person demobilized must sign a sworn statement affirming that he has not committed any crime other than those established in this provision,” the Court has already verified that this type of legal provision may be insufficient if, at the same time, the authorities in charge of the investigations or the office of the Prosecutor General fail to verify these affirmations rigorously (supra para. 166). Cf. Law 1312 of July 9, 2009 (evidence file, tome XXII, attachment 3 to the final arguments brief of the representatives, folios 9061 to 9063). 317 Case of the Mapiripán Massacre v. Colombia. Monitoring compliance with judgment, supra note 242, considering paragraphs 40 and 41.