488. […] The reasonable doubt standard in criminal law cannot consist in imaginary or frivolous doubt based on empathy or prejudice. It must be based on logic and common sense, and have a rational link to the evidence, lack of evidence or inconsistencies in the evidence. […] 

569. The Appeals Chamber of the ICTR has not previously endorsed a particular definition of the nexus requirement.[1] The Appeals Chamber of the ICTY has done so twice. The first time, in the Tadic Jurisdiction Decision, the Appeals Chamber stated that the offences had to be “closely related” to the armed conflict, but it did not spell out the nature of the required relation.[2] In the Kunarac Appeal Judgement, it endorsed the same standard. It then provided the following details, which appear relevant to the Prosecution appeal in this case:

58. What ultimately distinguishes a war crime from a purely domestic offence is that a war crime is shaped by or dependent upon the environment – the armed conflict – in which it is committed. It need not have been planned or supported by some form of policy. The armed conflict need not have been causal to the commission of the crime, but the existence of an armed conflict must, at a minimum, have played a substantial part in the perpetrator’s ability to commit it, his decision to commit it, the manner in which it was committed or the purpose for which it was committed. Hence, if it can be established, as in the present case, that the perpetrator acted in furtherance of or under the guise of the armed conflict, it would be sufficient to conclude that his acts were closely related to the armed conflict. The Trial Chamber’s finding on that point is unimpeachable.

59. In determining whether or not the act in question is sufficiently related to the armed conflict, the Trial Chamber may take into account, inter alia, the following factors: the fact that the perpetrator is a combatant; the fact that the victim is a non-combatant; the fact that the victim is a member of the opposing party; the fact that the act may be said to serve the ultimate goal of a military campaign; and the fact that the crime is committed as part of or in the context of the perpetrator’s official duties .[3]

570. This Chamber agrees with the criteria highlighted and with the explanation of the nexus requirement given by the ICTY Appeals Chamber in the Kunarac Appeal Judgement.  It is only necessary to explain two matters.  First, the expression “under the guise of the armed conflict” does not mean simply “at the same time as an armed conflict” and/or “in any circumstances created in part by the armed conflict”.  For example, if a non-combatant takes advantage of the lessened effectiveness of the police in conditions of disorder created by an armed conflict to murder a neighbour he has hated for years, that would not, without more, constitute a war crime under Article 4 of the Statute.  By contrast, the accused in Kunarac, for example, were combatants who took advantage of their positions of military authority to rape individuals whose displacement was an express goal of the military campaign in which they took part.  Second, as paragraph 59 of the Kunarac Appeal Judgement indicates, the determination of a close relationship between particular offences and an armed conflict will usually require consideration of several factors, not just one.  Particular care is needed when the accused is a non-combatant.

219. On this point, the Appeals Chamber refers to the opinion of the ICTY Appeals Chamber, which considers that in matters of evidence, there is no established rule that traumatic circumstances endured by a witness necessarily render his or her evidence unreliable.[1] In the instant case, it has not been demonstrated how the “trauma” would have rendered Witnesses AA and Q incapable of giving an accurate account of the events they experienced. Consequently, the Appeals Chamber considers that the Trial Chamber correctly held that the fact that a witness may forget or mix up small details is often as a result of trauma suffered and does not necessarily impugn his evidence in relation to the central facts of the crime.[2] Hence, the Appellant, by merely citing two paragraphs of the Judgement and raising general considerations, has in no way demonstrated the basis for his contention that the Trial Chamber in general discounted many contradictions in the evidence on grounds of trauma.

62. [...] There is no provision in the Rules that prohibits Judges from asking questions in order to contribute to discovering the truth or to try to corroborate or contradict the facts in issue. [...]

63. [...] As has already been recalled, the Rules allow Judges to ask questions, and Judges have a wide discretion to contribute to the discovery of the truth, including the power to confront one witness with the testimony of another. [...]

[...]

111. […] The Appeals Chamber recalls that it is up to the Judges to ask any questions that they deem necessary for the clarification of testimonies and for the discovery of the truth. […]

[…]

118. […] the Appeals Chamber considers that the questions fall entirely within the ambit of the Judge’s duty to contribute to the discovery of the truth, which implies, especially at the cross-examination phase, the possibility of testing witness credibility. […]

9.       […] The Appeals Chamber considers that there is no indication in Rule 70 that the rule applies only to the pre-appeal stage in a case.  By its nature, the material envisaged in Rule 70 (C), and therefore necessarily in Rule 70, may arise at the pre-trial, trial, or appeal stage.  The Appeals Chamber considers, therefore, that the expression of “non-public material which falls under Rule 70 (C)” applies to material falling under Rule 70 and introduced into the proceedings at all stages of the case, including the appeal.

9.       […] the Tribunal only has jurisdiction over a listed crime if that crime was recognised as such under customary international law at the time it was allegedly committed.[1] The scope of the Tribunal’s jurisdiction ratione materiae may therefore be said to be determined both by the Statute, insofar as it sets out the jurisdictional framework of the International Tribunal, and by customary international law, insofar as the Tribunal’s power to convict an accused of any crime listed in the Statute depends on its existence qua custom at the time this crime was allegedly committed.[2]

[…]

18.     […] A crime or a form of liability which is not provided for in the Statute could not form the basis of a conviction before this Tribunal.[3] The reference to that crime or to that form of liability does not need, however, to be explicit to come within the purview of the Tribunal’s jurisdiction.[4] The Statute of the ICTY is not and does not purport to be, unlike for instance the Rome Statute of the International Criminal Court, a meticulously detailed code providing explicitly for every possible scenario and every solution thereto. It sets out in general terms the jurisdictional framework within which the Tribunal has been mandated to operate.

37.     Secondly, the principle nullum crimen sine lege is, as noted by the International Military Tribunal in Nuremberg, first and foremost, a “principle of justice”.[1]  It follows from this principle that a criminal conviction can only be based on a norm which existed at the time the acts or omission with which the accused is charged were committed.  The Tribunal must further be satisfied that the criminal liability in question was sufficiently foreseeable and that the law providing for such liability must be sufficiently accessible at the relevant time for it to warrant a criminal conviction and sentencing under the head of responsibility selected by the Prosecution. 

38.     This fundamental principle “does not prevent a court from interpreting and clarifying the elements of a particular crime”.[2]  Nor does it preclude the progressive development of the law by the court.[3]  But it does prevent a court from creating new law or from interpreting existing law beyond the reasonable limits of acceptable clarification.  This Tribunal must therefore be satisfied that the crime or the form of liability with which an accused is charged was sufficiently foreseeable and that the law providing for such liability must be sufficiently accessible at the relevant time, taking into account the specificity of international law when making that assessment. 

39.     The meaning and scope of the concepts of “foreseeability” and “accessibility” of a norm will, as noted by the European Court of Human Rights,[4] depend a great deal on “the content of the instrument in issue, the field it is designed to cover and the number and status of those to whom it is addressed”.[5]  The specificity of international criminal law in that respect has been eloquently noted by one American Military Tribunal in Nuremberg in the Justice case:

Under written constitutions the ex post facto rule condemns statutes which define as criminal, acts committed before the law was passed, but the ex post facto rule cannot apply in the international field as it does under constitutional mandate in the domestic field.  […] International law is not the product of statute for the simple reason that there is yet no world authority empowered to enact statutes of universal application. International law is the product of multipartite treaties, conventions, judicial decisions and customs which have received international acceptance or acquiescence.  It would be sheer absurdity to suggest that the ex post facto rule, as known to constitutional states, could be applied to a treaty, a custom, or a common law decision of an international tribunal, or to the international acquiescence which follows the events. To have attempted to apply the ex post facto principle to judicial decisions of common international law would have been to strangle that law at birth.[6]

40.     […] This Tribunal does not apply the law of the former Yugoslavia to the definition of the crimes and forms of liability within its jurisdiction.  It does, as pointed out above, apply customary international law in relation to its jurisdiction ratione materiae.  It may, however, have recourse to domestic law for the purpose of establishing that the accused could reasonably have known that the offence in question or the offence committed in the way charged in the indictment was prohibited and punishable.  […]

41.     Although domestic law (in particular the law of the country of the accused) may provide some notice to the effect that a given act is regarded as criminal under international law, it may not necessarily provide sufficient notice of that fact.  Customary law is not always represented by written law and its accessibility may not be as straightforward as would be the case had there been an international criminal code.  But rules of customary law may provide sufficient guidance as to the standard the violation of which could entail criminal liability.[7]  […]

42.     […] Although the immorality or appalling character of an act is not a sufficient factor to warrant its criminalisation under customary international law, it may in fact play a role in that respect, insofar as it may refute any claim by the Defence that it did not know of the criminal nature of the acts.[8] 

See also para. 10.

25.     Joint criminal enterprise is different from membership of a criminal enterprise which was criminalised as a separate criminal offence in Nuremberg and in subsequent trials held under Control Council Law No 10.[1]  As pointed out by the United Nations War Crimes Commission, what was to be punished in relation to the latter was “no mere conspiracy to commit crimes but a knowing and voluntary membership of organisations which did in fact commit crimes, and those on a wide scale”.[2]  No such offence was included in the Tribunal’s Statute.  The Secretary-General made it clear that only natural persons (as opposed to juridical entities) were liable under the Tribunal’s Statute,[3] and that mere membership in a given criminal organization would not be sufficient to establish individual criminal responsibility:

The question arises, however, whether a juridical person, such as an association or organization, may be considered criminal as such and thus its members, for that reason alone, be made subject to the jurisdiction of the International Tribunal. The Secretary-General believes that this concept should not be retained in regard to the International Tribunal. The criminal acts set out in this Statute are carried out by natural persons; such persons would be subject to the jurisdiction of the International Tribunal irrespective of membership in groups.[4]

26.     Criminal liability pursuant to a joint criminal enterprise is not a liability for mere membership or for conspiring to commit crimes, but a form of liability concerned with the participation in the commission of a crime as part of a joint criminal enterprise, a different matter.  […]

22.     A Trial Chamber of the International Tribunal is in nature both a trier of fact and an arbiter of questions of law.  Authorised by the Statute and the Rules to make factual findings on the basis of evidence presented by the parties, the Trial Chamber relies on the factual findings to determine the guilt or innocence of the accused.  In that sense, the factual findings, subject to appeal and review, are parts of the truth proved beyond reasonable doubt.[1]  It does not, however, follow that the Trial Chamber, by assessing evidence presented by the parties, will be discharging some of the prosecutorial responsibilities.

7.       Two of the appellants (Landžo and Mucić) initially argued that the Appeals Chamber had no power to remit limited issues such as the adjustment of a sentence to a Trial Chamber for its determination.[1]  The third of the appellants (Delić) accepted that the Appeals Chamber had power to remit a limited issue to a Trial Chamber, but he submitted that it should not have done so in this case where none of the judges of the original Trial Chamber could be a member of the new Trial Chamber.[2]

9.       The argument originally put as to the power of the Appeals Chamber to remit limited issues to a new Trial Chamber would in any event have been rejected.  The Appeals Chamber considered its power to do so at the time when it exercised that power in its judgment in the earlier appeal.  An appeal from the Trial Chamber’s determination of those limited issues does not give to the parties the opportunity to appeal against the decision of the Appeals Chamber to remit those limited issues to the Trial Chamber.

10.     Nor does the Appeals Chamber consider it appropriate to reconsider its power to remit limited issues to a new Trial Chamber.  Its power to remit limited issues is clear. [….]

16.     The powers of the Appeals Chamber in relation to an appeal are not limited to those expressly stated in Article 25 of the Tribunal’s Statute or in Rule 117(C).  As part of the Tribunal, it also has an inherent power, deriving from its judicial function, to control its proceedings in such a way as to ensure that justice is done.[3]  The circumstances previously outlined prevented the Appeals Chamber from exercising its power to resolve those issues itself.  In those circumstances, it had the inherent power to remit those issues to be determined by another Chamber to ensure that justice was done to the parties in relation to the issues raised by the Appeals Chamber Judgment.[4]  The challenge to the power of the Appeals Chamber to remit limited issues is rejected.

See also para. 3.