41. The Appeals Chamber recalls that once the requirement of a widespread or systematic attack against a civilian population is fulfilled, there must be a nexus between the acts of the accused and the attack itself. The Appeals Chamber considers that, as correctly noted by the Prosecution,[1] the requirement that the acts of an accused must be part of the “attack” against the civilian population does not, however, require that they be committed in the midst of that attack: a crime which is committed before or after the main attack against the civilian population or away from it could still, if sufficiently connected, be part of that attack.[2] Hence, the fact that the crimes committed in Ovčara took place after the widespread and systematic attack against the civilian population of Vukovar cannot in itself be determinative of whether the nexus requirement was met. Such a nexus consists of two elements:

(i) the commission of an act which, by its nature or consequences, is objectively part of the attack; coupled with

(ii) knowledge on the part of the accused that there is an attack on the civilian population and that his act is part thereof.[3]

Thus, to convict an accused of crimes against humanity, it must be proven that his acts were related to a widespread or systematic attack against a civilian population and that he knew that his acts were so related. Such an assessment will be made on a case-by-case basis. For example, having considered the context and circumstances in which an act was committed, an act may be so far removed from the attack that no nexus can be established (so called “isolated act”) and hence cannot qualify as a crime against humanity.[4]

42. In the present case, after reviewing the evidence before it, the Trial Chamber concluded that the perpetrators of the crimes committed against the prisoners in Ovčara selected the individuals based on their involvement in the Croatian armed forces. The Trial Chamber found:

While there may have been a small number of civilians among the 194 identified murder victims charged in the Indictment, in the Chamber’s finding, the perpetrators of the offences against the prisoners at Ovčara on 20/21 November 1991 charged in the Indictment, acted in the understanding that their acts were directed against members of the Croatian forces.”[5]

The Appeals Chamber concurs with the Trial Chamber’s assessment of the evidence in the trial record. The crimes in Ovčara were directed against a specific group of individuals,[6] the victims of the crimes were selected based on their perceived involvement in the Croatian armed forces,[7] and as such treated “differently from the civilian population”.[8] The Prosecution’s arguments that the crimes occurred two days after the fall of Vukovar, that Ovčara was located within the geographical scope of the attack against Vukovar, that the perpetrators of the crimes in Ovčara also participated in the attack against the civilian population in Vukovar, and that the perpetrators of the crimes “harboured intense feeling of animosity towards persons they perceived as enemy forces,[9] do not undermine the Trial Chamber’s findings, unchallenged by the Parties, that the perpetrators of the crimes in Ovčara acted in the understanding that their acts were directed against members of the Croatian armed forces. The fact that they acted in such a way precludes that they intended that their acts form part of the attack against the civilian population of Vukovar and renders their acts so removed from the attack that no nexus can be established.

43. The Appeals Chamber finds that the requirement of a nexus between the acts of the accused and the attack itself was not established and that, in the absence of the required nexus under Article 5 of the Statute between the crimes committed against the prisoners at Ovčara and the widespread or systematic attack against the civilian population of Vukovar, the crimes committed cannot be qualified as crimes against humanity. Thus, even though the Trial Chamber erred in law by adding a requirement that the victims of the underlying crimes under Article 5 of the Statute be civilians, the Appeals Chamber concurs with the Trial Chamber – albeit for different reasons – that the “jurisdictional prerequisites of Article 5 of the Statute have not been established”.[10]

100. The acts of the accused must be part of the “attack” against the civilian population, but they need not be committed in the midst of that attack. A crime which is committed before or after the main attack against the civilian population or away from it could still, if sufficiently connected, be part of that attack. The crime must not, however, be an isolated act.[1]  A crime would be regarded as an “isolated act” when it is so far removed from that attack that, having considered the context and circumstances in which it was committed, it cannot reasonably be said to have been part of the attack.[2]