916. According to the Kunarac et al. Trial Judgement, an attack “can be described as a course of conduct involving the commission of acts of violence”.[1] This characterization was endorsed by the Appeals Chamber of ICTY,[2] which added the following:

The concepts of “attack” and “armed conflict” are not identical. Under customary international law, the attack could precede, outlast, or continue during the armed conflict, but it need not be a part of it. Also, the attack in the context of a crime against humanity is not limited to the use of armed force; it encompasses any mistreatment of the civilian population.[3]

917. This position is reiterated in the Kordić and Čerkez Appeal Judgement[4] and was adopted in a number of ICTY Trial judgements^.[5] According to the Kayishema and Ruzindana Trial Judgement:

The attack is the event of which the enumerated crimes must form part. Indeed, within a single attack, there may exist a combination of the enumerated crimes, for example murder, rape and deportation.[6]

918. In agreement with these authorities, the Appeals Chamber concludes that, for purposes of Article 3 of the Statute, an attack against a civilian population means the perpetration against a civilian population of a series of acts of violence, or of the kind of mistreatment referred to in sub-paragraphs (a) to (i) of the Article.[7] […]

920. […] It is well established that the attack must be widespread or systematic.[8] In particular, the Appeals Chamber has held that the conjunction “et” in the French version of Article 3 of the Statute is a translation error.[9] The Appeals Chamber further recalls that:

“widespread” refers to the large-scale nature of the attack and the number of victims, whereas “systematic” refers to “the organised nature of the acts of violence and the improbability of their random occurrence.” Patterns of crimes – that is the non-accidental repetition of similar criminal conduct on a regular basis – are a common expression of such systematic occurrence.[10]

In this particular case, the Appeals Chamber concluded that the Prosecution had not proven beyond reasonable doubt that there was a widespread or systematic attack against Tutsi civilians in Rwanda between 1 January and 6 April 1994 (paras 929-933). However, it held that “[w]hereas the crime per se must be committed as part of a widespread and systematic attack, preparatory acts, instigation or aiding and abetting can be accomplished before the commission of the crime and the occurrence of the widespread and systematic attack[11]” (para. 934).

389. An enumerated crime under Article 3 of the Statute constitutes a crime against humanity if it is proven to have been committed as part of a widespread or systematic attack against a civilian population on national, political, ethnic, racial or religious grounds.[1] The term “widespread” refers to the large scale nature of the attack and the number of victims, whereas the term “systematic” refers to “the organised nature of the acts of violence and the improbability of their random occurrence”.[2] With respect to the mens rea, the perpetrator must have acted with knowledge of the broader context of the attack, and with knowledge that his acts (or omissions) formed part of the widespread or systematic attack against the civilian population.[3]

390. The Trial Chamber correctly articulated these required elements of crimes against humanity[4] and, contrary to Nsengiyumva’s contention, provided a reasoned opinion for its conclusion that the totality of the evidence established that these required elements were met.[5] Nsengiyumva’s argument that the Trial Chamber erred in “taking the country of Rwanda as one crime scene” implies that, in order to qualify as crimes against humanity, the attacks in Gisenyi should have been shown to have been widespread or systematic independently of attacks taking place elsewhere in Rwanda. Such a suggestion is, however, erroneous, as the requirement is that the attacks be committed within a broader context, that is, as part of a widespread or systematic attack.[6] Nsengiyumva fails to show that the Trial Chamber erred in holding that this requirement was satisfied.

101. In relation to the widespread or systematic nature of the attack, the Appeals Chamber recalls the jurisprudence of the International Tribunal according to which the phrase “widespread” refers to the large-scale nature of the attack and the number of targeted persons, while the phrase “systematic” refers to the organized nature of the acts of violence and the improbability of their random occurrence.[1] Patterns of crimes, in the sense of the non-accidental repetition of similar criminal conduct on a regular basis, are a common expression of such systematic occurrence.[2] Only the attack, not the individual acts of the accused, must be widespread or systematic.[3] The Appeals Chamber underscores that the acts of the accused need only be a part of this attack, and all other conditions being met, a single or limited number of acts on his or her part would qualify as a crime against humanity, unless those acts may be said to be isolated or random.[4]