The case concerns the mistreatment and execution of Croat and other non-Serb individuals taken from the Vukovar hospital by Serb forces. Mrkšić was a colonel in the JNA and commander of the Guards Motorised Brigade and Operational Group South. Šljivančanin was a major in the JNA and held the post of head of the security organ of both the Guards Motorised Brigade and the OG South. The Trial Chamber convicted them for, inter alia, aiding and abetting torture and inhumane treatment. The parties and Prosecutor appealed. The Appeals Chamber found that the Trial Chamber properly considered aiding and abetting by omission.
In the context of omission:
1. “Failure to discharge a legal duty assisted, encouraged or lent moral support to the perpetration of the crime” with a “substantial effect on the realisation of that crime” (¶ 49)
3. Knowledge “that his omission assists in the commission of the crime of the principal perpetrator and must be aware of the essential elements of the crime which was ultimately committed by the principal” (¶ 49)
ACTUS REUS: An omission may constitute the actus reus if, “at a minimum, all the basic elements of aiding and abetting [are] fulfilled” (¶ 49). Further, “aiding and abetting by omission implicitly requires that the accused had the ability to act, such that there were means available to the accused to fulfil his duty” (¶ 49).
With respect to the specific direction standard, the Appeals Chamber found that “‘specific direction’ is not an essential ingredient of the actus reus of aiding and abetting” (¶ 159).