117. The jurisprudence on this issue is clear. Joint criminal enterprise requires the existence of a common purpose which amounts to or involves the commission of a crime. The common purpose need not be previously arranged or formulated; it may materialize extemporaneously.[1]

118. In the Krnojelac Appeal Judgement, the Appeals Chamber confirmed that the systemic form of joint criminal enterprise does not require proof of an agreement:

The Appeals Chamber considers that, by requiring proof of an agreement in relation to each of the crimes committed with a common purpose, when it assessed the intent to participate in a systemic form of joint criminal enterprise, the Trial Chamber went beyond the criterion set by the Appeals Chamber in the Tadić case. Since the Trial Chamber’s findings showed that the system in place at the KP Dom sought to subject non-Serb detainees to inhumane living conditions and ill-treatment on discriminatory grounds, the Trial Chamber should have examined whether or not Krnojelac knew of the system and agreed to it, without it being necessary to establish that he had entered into an agreement with the guards and soldiers – the principal perpetrators of the crimes committed under the system – to commit those crimes.[2]