A/HRC/45/13/Add.3 47. The statute of limitations does not apply to enforced disappearances as a crime against humanity, whether this is defined as a widespread or systematic practice of enforced disappearance43 or as a single act of enforced disappearance.44 48. In instances of connivance of judicial structures with the perpetrators, the Working Group has observed situations where there have been intentionally superficial investigations aimed at acquitting the accused and granting them judicial protection through the principles of res judicata and ne bis in idem. 49. Terminating investigations in a fraudulent manner, or even through an amnesty law, can in some legal systems lead to the inability to reopen them, owing to the abovementioned principles. Accordingly, the principle of double jeopardy, although recognized as a judicial guarantee in the International Covenant on Civil and Political Rights, is not absolute in nature and cannot be resorted to in order to perpetuate impunity.45 It has been established that States should adopt safeguards against this type of abuse,46 such as ensuring the possibility of reopening investigations. III. Public policies for an efficient investigation of enforced disappearances 50. The Working Group has identified several underlying obligations concerning the duty to investigate that require the enforcement of specific public policies, which are vital to the obligation itself. A. Obligation to criminalize enforced disappearance autonomously 51. The obligation of the State to qualify enforced disappearance as an independent crime, as provided for in article 4 of the Declaration on the Protection of All Persons from Enforced Disappearance, is a critical requirement for an efficient investigation. This qualification enables the authorities in charge to understand the specific nature of the offence and to initiate a prompt, proper and effective investigation into the allegations. In the Working Group’s experience, acts amounting to enforced disappearance are sometimes investigated and prosecuted as other crimes, such as kidnapping, torture, murder and illegal deprivation of liberty, owing to the lack of a specifically codified offence of enforced disappearance. This creates a situation in which suspected perpetrators of enforced disappearances can be acquitted if the standards of proof for the crimes of which they are accused are not met.47 52. The Working Group has also noticed that in those countries where enforced disappearances are investigated and prosecuted under other criminal definitions, the sanctions are often not commensurate with the extreme seriousness of the crime. 53. As enforced disappearances usually take place within organized State power structures, or are perpetrated by criminal groups benefiting from the support or acquiescence of the State, the Working Group has recommended the criminalization of the multiple types of participation or responsibility. 48 Although the Declaration does not expressly establish the responsibility of superiors, article 6, paragraph 1, of the International Convention on the Protection of All Persons from Enforced Disappearance does, as it explicitly requires States to take the necessary steps to criminalize: 43 44 45 46 47 48 10 International Convention, art. 5. A/HRC/45/13/Add.2, para. 19. Inter-American Court of Human Rights, Almonacid-Arellano et al. v. Chile, Judgment, 26 September 2006, par. 154, which contains the classification of three types of fraudulent double jeopardy, namely: (a) when a court acted towards exempting the defendant from the charge of serious violations to human rights of their criminal responsibility; (b) when the proceeding was not independently and impartially carried out, following due process; and (c) when there was no actual intent to subject the defendant to any legal action. E/CN.4/2005/102/Add.1, principle 22. A/HRC/39/46/Add.1, para. 30; and A/HRC/33/51/Add.1, para. 15. A/HRC/16/48/Add.3, para. 62.