• T he general socio-historical context of the events. This is particularly important where there is a reasonable hypothesis that political authorities knew of, tolerated or aided and abetted the crimes in question. Several countries have witnessed crimes committed by official forces while apparently under democratic rule. To present an accurate understanding of how these events can occur, it is important for the investigation to uncover the real nature of the political, historical and institutional relationships. Again, this work generally requires historians and political scientists, rather than lawyers. • The local context and dynamics of violence. System crimes generally occur in the context of a real or perceived threat to the established political order, such as political opposition or armed resistance. Studies of areas where violence has occurred can be significant for a number of reasons. First, when the alleged crimes took place several years earlier and in places not well known to investigators, such studies allow them to understand more clearly the context of the investigation. This will help them to develop the lines of investigation more effectively and relate more easily to potential witnesses. Furthermore, understanding the local social, political and cultural dynamics at the time the crimes were committed will help in anticipating lines of defence and allow the investigation to develop hypotheses and counter-hypotheses. • Analysis of public and restricted documentary information. Recovering and analysing documentary information is often vital to the success of these investigations. Documentary evidence may have advantages over personal testimony, as it may help to prove matters more quickly and succinctly. It is not subject to the difficulties presented by intimidation and changing disposition of witnesses. Although always subject to interpretation, it can often provide more conclusive evidence of specific events or orders than personal recollections or conjectures. • Crime-base reconstruction. This relates to the more traditional business of gathering personal testimonies and forensic evidence to recreate the scene where the criminal act was committed. One of the main difficulties is that most investigative forces base their expertise on crime-scene reconstruction and forensic analysis. This is increasingly so because of the technological advances in forensic pathology. Regardless of the crime, it is clearly essential to prove the facts of the criminal act; however, this procedure alone generally cannot provide the proof of participation of those behind the scenes. Most investigative bodies are not trained to prove such participation through different forms of analysis. The tendency is to overload investigations with crime-scene information that ultimately proves only that a great number of criminal acts were committed. It does not clarify the nature of participation in these crimes or the identity of the intellectual authors. Expert capacity in investigating system crimes rarely exists in countries grappling with a legacy of massive crimes. Various models of assistance might be contemplated, but it is important to understand the relationship between the mapping exercise and the capacity demands. The goal should not be to reform the entire justice system at the exact same pace, but rather to 13