A/HRC/20/14 34. Regional courts have made the point that prosecution or extradition of individuals alleged to be responsible for unlawful killings serves as a measure of prevention. 52 In this way, the State’s duty to investigate and prosecute terrorist suspects is directly linked to its obligation to end impunity and prevent future acts of terrorism. Individuals suspected, on objectively reasonable grounds, of having engaged in the incitement, preparation, instigation or commission of terrorist acts should be duly investigated and, if appropriate, prosecuted, convicted and punished according to the ordinary rules of criminal law and procedure,53 or else extradited to another State to face trial. This implies, in either event, that the eventual trial of a person accused of involvement in an act of terrorism will meet international standards for a fair and public hearing before an independent and impartial civilian court. A public court hearing provides visible justice to the victims and their families. In contrast, indefinite or secret detention of terrorist suspects, without charge or trial, is not only contrary to international law54 but also precludes the possibility of victim participation in the process of bringing offenders to justice. 35. The Special Rapporteur concurs with the view of the European Court of Human Rights that the State’s obligation to protect life requires an effective official investigation whenever individuals have been killed or sustained life-threatening injuries through the use of lethal or potentially lethal force in a terrorist context, whether from an unlawful act of terrorism committed by a non-State actor, or from the acts or omissions of public officials in the implementation of counter-terrorism strategies.55 36. In its evolving jurisprudence, the European Court of Human Rights has established a number of criteria to assess the effectiveness of such an investigation, which may be discharged by an inquest, a public inquiry, an independent investigation or a combination of mechanisms. The State’s obligation cannot however be discharged merely through the availability of a civil remedy at the initiative of the victim or his/her next-of-kin. In the Special Rapporteur’s view, the following minimum requirements must be satisfied in every case: • Once the matter has come to the attention of the authorities, they must act ex officio and not wait for a formal complaint lodged by the deceased's next of kin.56 This applies not only to deaths resulting from a lethal terrorist act, but also to deaths caused by State officials during a counter-terrorist operation, and cases where it is plausibly alleged that public officials have culpably failed in the responsibility to take preventive measures to avert an act of terrorism. • The investigation should always begin promptly. A timely investigation is more likely to secure reliable evidence. While there may be obstacles delaying progress in an investigation, it must be carried out with reasonable expedition.57 52 53 54 55 56 57 See for example ECHR, Kaya v. Turkey, no. 22535/93, para. 85. See A/HRC/16/51, practice 3, para. 1; also Human Rights Committee general comment No. 6 (1982), para. 3; CCPR/CO/73/UK;CCPR/CO/73/UKOT, para. 8. Even where States have entered formal derogations, in international or regional human rights instruments on grounds of national emergency, measures of detention must nevertheless be exceptional and temporary in nature and the extent of the derogation must, in all respects, meet the standards of proportionality and non-discrimination; see for example ECHR, A and others v. The United Kingdom, no. 3455/05. ECHR, Branko Tomašić and Others v. Croatia, no. 46598/06, para. 62. See also ECHR, İlhan v. Turkey, no. 22277/93, para. 63 See for example ECHR, Yaşa v. Turkey, no. 22495/93, paras. 102-104; Cakıcı v. Turkey, no. 23657/94, paras. 80, 87 and 106; Mahmut Kaya v. Turkey, no. 22535/93, paras. 106-107; Isayeva, Yusupova and Bazayeva v. Russia, nos. 57947-49/00, para. 212; Benuyeva and Others v. Russia, no. 8347/05, para. 112. 11