A/HRC/20/14 jurisdiction. Consequently, (i) the State has a duty under international law to put in place effective criminal law provisions to deter the incitement, preparation and commission of terrorist offences, supported by law-enforcement machinery for the prevention, suppression and sanctioning of breaches; (ii) relevant public officials come under a positive operational duty to take preventative action where they know, or ought to know, of the existence, at the relevant time, of a real and immediate risk to the life of an identified individual or group of individuals, and yet fail to take measures, within the scope of their legal powers and available resources, and in conformity with the State's international obligations, which judged reasonably, might be expected to avoid that risk. (b) Individuals suspected of having engaged in the incitement, preparation, instigation or commission of acts of terrorism should be duly investigated, and if appropriate, prosecuted, convicted and punished, according to the ordinary rules of criminal law and procedure, or else extradited to face trial in another jurisdiction. This implies a fair and public hearing before an independent and impartial civilian court. States are under a duty to provide mutual legal assistance in the investigation and prosecution of terrorist offences and to cooperate, as far as they consider reasonable, in the exchange of intelligence with other States. These duties, however, take effect subject to the a priori obligation of all States to refuse such assistance where it would entail the commission of, complicity in, or any form of direct or indirect assistance to, an internationally wrongful act, including any violation of international human rights law. (c) The State is obliged to conduct an effective official investigation whenever individuals have been killed or seriously injured as the direct or indirect result of an act of terrorism, with a view to securing accountability and learning lessons for the future. The key features of such an investigation are that (i) the authorities must act ex officio; (ii) the investigation should always begin promptly and be carried out with reasonable expedition; (iii) the authorities must ensure that the victim or his/her next-of-kin are kept fully informed of the progress of the investigation, and are provided with an adequate opportunity to participate in the process; (iv) investigators must be genuinely impartial; (v) the investigation must be capable of leading to the identification, accountability and, where appropriate, the punishment of those responsible for any act or omission which has caused or contributed to the death or serious physical or psychological injury of a victim of terrorism, including any public official implicated in the events; (vi) there must be a sufficient element of public scrutiny of the investigation and its results to secure accountability; (vii) the authorities must have taken all reasonable steps to secure the relevant evidence; and (viii) any conclusions must be based on a complete, objective and impartial analysis of all relevant elements, including an examination of the authorities’ own actions. Where State responsibility is at issue the investigative authorities must be independent from those potentially implicated. (d) Making due allowance for the differences in national systems, the Special Rapporteur strongly recommends that States which currently have no possibility for a victim of terrorism or his/her next-of-kin to play an active part in criminal proceedings (other than as witnesses of fact) should give serious and urgent consideration to implementing a system for effective victim participation. (e) The victim or the victim's family must in all cases be provided with the information necessary to exercise any rights they may have in domestic law to participate in judicial proceedings. In this connection, (i) States should establish a support service to assist the victim in the process; (ii) legal aid or assistance should be accorded so as to ensure that victims can participate effectively; (iii) provision should 19