III.  ACCOUNTABILITY AND THE RIGHTS OF VICTIMS Concerning the superior’s “duty to prevent” established in article 87.2 of Protocol I, the Appeals Chamber indicated that the general duty of commanders to take the necessary and reasonable measures was well rooted in customary international law and stemmed from their position of authority. It stated that the “‘necessary’ measures are the measures appropriate for the superior to discharge his obligation (showing that he genuinely tried to prevent or punish) and ‘reasonable’ measures are those reasonably falling within the material powers of the superior.” Thus, the standard is whether the superior failed to take the necessary and reasonable measures to prevent the criminal act or punish the perpetrator.118 2.  The obligations of States regarding international crimes Where violations of international human rights and humanitarian law constitute international crimes, States have a series of legal obligations and responsibilities that stem from international criminal law. States have the duty to investigate violations and, if there is sufficient evidence, the duty to submit to prosecution the person allegedly responsible for them and to punish the perpetrator in accordance with the law, to exclude the possibility of amnesty for certain perpetrators, and to offer remedy and reparation to victims or their families. Their obligation to extend jurisdiction for prosecution of such crimes beyond their territory will be discussed in the next subsection. The obligation to seek accountability includes a responsibility for States, in accordance with international law, to cooperate with one another and assist international judicial organs competent in the investigation and prosecution of these violations. The obligation to seek accountability is explicitly referred to in some instruments of international human rights and humanitarian law and has been reinforced by interpretations of the law. The International Covenant on Civil and Political Rights,119 the Convention against Torture, the   Prosecutor v. Sefer Halilovic´, case No. IT-01-48-A, Judgement of 16 October 2007, paras. 63–64. 119   For example, article 2.3 states that “[e]ach State Party to the present Covenant undertakes: (a) [t]o ensure that any person whose rights or freedoms as herein recognized are 118 81