A/HRC/39/46 60. Article 17 of the Declaration also establishes that, when the remedies provided for in article 2 of the International Covenant on Civil and Political Rights are no longer effective, statutes of limitations related to acts of enforced disappearances should be suspended until these remedies are re-established. In addition, it provides that where they exist, statutes of limitations relating to acts of enforced disappearance should be commensurate with the extreme seriousness of the offence. When the crime is committed in the context of a widespread or systematic practice, as in a crime against humanity, there should be no kind of statute of limitations.30 61. Furthermore, it is clear that investigations related to enforced disappearance should be carried out until the fate of the disappeared is clarified 31 and that this should be done within a reasonable time frame. 62. Articles 13 of the Declaration and 12 of the Convention contain an important set of principles to guide States in the investigation of enforced disappearances, beginning with the right to complain to a competent and independent State authority, and to have the complaint promptly, thoroughly and impartially investigated. Among those principles, the following could be highlighted: (a) investigative authorities should have access to any place of detention, official or not; 32 (b) the investigation should be undertaken without delay, even ex officio, without formal complaint; 33 (c) those suspected of having been involved in the disappearance should not have the possibility of influencing the investigation through pressure, acts of intimidation or reprisals;34 (d) State agencies the members of which could be involved in the disappearance should not participate in the investigations (see A/HRC/33/51/Add.2, para. 82 (a), and CED/C/MEX/CO/1, para. 28 (d)); (e) authorities should have the necessary powers and resources to conduct investigations, including powers to compel the attendance of witnesses and the production of the relevant documents, including military, police and intelligence files. 35 63. The study will also analyse the obligation of States on mutual cooperation in criminal proceedings, taking into consideration that, in the experience of the Working Group, enforced disappearance often manifests itself as a transnational crime, as described in the latest thematic report on enforced disappearances in the context of migration (see A/HRC/36/39/Add.2, para. 83). 64. The independence of the prosecution and the impartiality of the judgments also appear as guarantees that support the whole scheme of rights and State obligations to develop the duty to investigate. In this sense, the Declaration establishes that those accused of having committed an enforced disappearance should be tried by the competent ordinary courts and not by other special tribunals, in particular military courts. 36 65. Finally, relatives of the disappeared have proven to be essential in the context of investigations and should have the right to know the truth, be granted full access to the investigation and participate in the proceedings. 30 31 32 33 34 35 36 See art. 5 of the Convention. The Working Group has always considered that, due to the continuous nature of the crime, it must be interpreted that the statutes of limitations, if applicable, should commence from the moment when the enforced disappearance ceases. See art. 13 (6) of the Declaration. See also art. 9 of the Declaration. See art. 13 (1) of the Declaration and art. 12 (2) of the Convention. See art. 12 (4) of the Convention. See art. 13 (2) of the Declaration and principle 16 of the updated set of principles for the protection and promotion of human rights through action to combat impunity (E/CN.4/2005/102/Add.1). See art. 16 (2) of the Declaration. See also the statement on enforced disappearance and military jurisdiction by the Committee on Enforced Disappearances (https://tbinternet.ohchr.org/Treaties/CED/Shared%20Documents/1_Global/INT_CED_SUS_7639_E. pdf, para. 3) and art. IX of the Inter-American Convention on Forced Disappearance of Persons. 9