CCPR/C/GC/35 threat is invoked to justify the detention of persons considered to present such a threat, the burden of proof lies on States parties to show that the individual poses such a threat and that it cannot be addressed by alternative measures, and that burden increases with the length of the detention. States parties also need to show that detention does not last longer than absolutely necessary, that the overall length of possible detention is limited and that they fully respect the guarantees provided for by article 9 in all cases. Prompt and regular review by a court or other tribunal possessing the same attributes of independence and impartiality as the judiciary is a necessary guarantee for those conditions, as is access to independent legal advice, preferably selected by the detainee, and disclosure to the detainee of, at least, the essence of the evidence on which the decision is taken.37 16. Egregious examples of arbitrary detention include detaining family members of an alleged criminal who are not themselves accused of any wrongdoing, the holding of hostages and arrests for the purpose of extorting bribes or other similar criminal purposes. 17. Arrest or detention as punishment for the legitimate exercise of the rights as guaranteed by the Covenant is arbitrary, including freedom of opinion and expression (art. 19),38 freedom of assembly (art. 21), freedom of association (art. 22), freedom of religion (art. 18) and the right to privacy (art. 17). Arrest or detention on discriminatory grounds in violation of article 2, paragraph 1, article 3 or article 26 is also in principle arbitrary.39 Retroactive criminal punishment by detention in violation of article 15 amounts to arbitrary detention.40 Enforced disappearances violate numerous substantive and procedural provisions of the Covenant and constitute a particularly aggravated form of arbitrary detention. Imprisonment after a manifestly unfair trial is arbitrary, but not every violation of the specific procedural guarantees for criminal defendants in article 14 results in arbitrary detention.41 18. Detention in the course of proceedings for the control of immigration is not per se arbitrary, but the detention must be justified as reasonable, necessary and proportionate in the light of the circumstances and reassessed as it extends in time. 42 Asylum seekers who unlawfully enter a State party’s territory may be detained for a brief initial period in order to document their entry, record their claims and determine their identity if it is in doubt. 43 To detain them further while their claims are being resolved would be arbitrary in the absence of particular reasons specific to the individual, such as an individualized likelihood of absconding, a danger of crimes against others or a risk of acts against national security. 44 The decision must consider relevant factors case by case and not be based on a mandatory rule for a broad category; must take into account less invasive means of achieving the same ends, such as reporting obligations, sureties or other conditions to prevent absconding; and 37 38 39 40 41 42 43 44 On the relationship of article 9 to article 4 of the Covenant and international humanitarian law, see paragraphs 64 to 67 below. 328/1988, Zelaya Blanco v. Nicaragua, para. 10.3. 1314/2004, O’Neill and Quinn v. Ireland, para. 8.5 (finding no violation); see concluding observations: Honduras (CCPR/C/HND/CO/1, 2006), para. 13 (detention on the basis of sexual orientation), and Cameroon (CCPR/C/CMR/CO/4, 2010), para. 12 (imprisonment for consensual same-sex activities of adults). 1629/2007, Fardon v. Australia, para. 7.4 (b). 1007/2001, Sineiro Fernández v. Spain, paras. 6.3 (absence of review of conviction by higher court violated paragraph 5 of article 14, but not paragraph 1 of article 9). 560/1993, A. v. Australia, paras. 9.3–9.4; 794/1998, Jalloh v. Netherlands, para. 8.2; 1557/2007, Nystrom v. Australia, paras. 7.2–7.3. 1069/2002, Bakhtiyari v. Australia, paras. 9.2–9.3. 1551/2007, Tarlue v. Canada, paras. 3.3 and 7.6; 1051/2002, Ahani v. Canada, para. 10.2. 5