A/HRC/8/14* page 9 (e) Command responsibility 14. In The Prosecutor v. Enver Hadzihasanovic (hereafter Hadzihasanovic),20 the Appeals Chamber of the ICTY analysed the different component of the notion of command responsibility. The Appeals Chamber recalled that a commander’s de jure power creates a presumption of effective control. However, the prosecution has the burden of proving beyond reasonable doubt that the accused had effective control over his subordinates. 15. The Appeals Chamber further discussed in Hadzihasanovic the scope of the “had reason to know” standard and indicated that the commander’s responsibility would be engaged if he fails to act in spite of the fact that he possessed sufficiently alarming information about possible violations. The Chamber indicates that “while the superior’s knowledge of and failure to punish his subordinates past offences is insufficient, in itself, to conclude that the superior know that similar offences would be committed by the same group of insubordinates, this may … nevertheless constitute sufficiently alarming information to justify further inquiry”.21 Thus, the Appeals Chamber interpreted the “reason to know” standard as requiring an assessment of whether a superior had sufficiently alarming information that would have alerted him of the risk that crimes might be committed by his subordinates. 16. Concerning the causality link in evaluating command responsibility, the Appeals Chamber in Hadzihasanovic made it clear that the determination of a causal link between a commander’s failure to act and his subordinate’s crimes was unnecessary to a finding of superior responsibility. The Chamber recalled the Trial Chamber’s conclusion in The Prosecutor v. Sefer Halilovic (hereafter Halilovic) that “if a causal link were required, this would change the basis of command responsibility for failure to prevent or punish to the extent that it would practically require involvement on the part of the commander in the crime his subordinates committed”.22 17. The Appeals Chamber in Halilovic also discussed the superior’s “duty to prevent” and indicated that the general duty of commanders to take the necessary and reasonable measures is well rooted in customary international law and stems from their position of authority. The Appeals Chamber 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.23 Thus, the standard is whether the superior failed to take the necessary and reasonable measures to prevent the criminal act or punish the perpetrator thereof.24 20 Case No. IT-01-47-A. 21 Ibid., para. 30. 22 Case No. IT-01-48-T, para. 78. 23 Case No. IT-01-48-A, para. 63. 24 Ibid., para. 64.