Using a field study as its basis, this report considers factors such as group behaviour, combat stress, media coverage and obedience to orders, and how they may be contributory causes in cases of military misconduct and ultimately war crimes. In broad terms, this report suggests that a sequence or combination of factors may together cause some cases of war crimes and other military misconduct, and that such cases may not simply be the result of the deliberate intent or actions of "evil" or disturbed individuals. In this case, this combination of factors over time seems to have resulted in frustration leading to aggression and poor leadership, mediated by group identity and group values. All the factors described here are likely to present in a conflict situation, and this suggests that any military unit runs the risk of serious misconduct under certain circumstances. Similar situations and problems may arise in other organisations with clear roles in society, such the police. Dealing with stress factors would be one way to prevent misconduct. This requires that commanders are trained to detect signs of stress and to action to reduce the stress in some way. However, this must also be supported by methods to identify operations and situations which can lead to negative stress and the risk of misconduct and, based on this, the development of suitable mitigation measures to reduce the likelihood of misconduct. For the military the report recommends that care be taken when selecting which military units to deploy on peacekeeping missions in order to balance mission demands, unit capabilities and operational risk, so as to try to reduce the likelihood of war crimes being committed. The use of military units in peacekeeping missions should be controlled, given that some of the preconditions for unacceptable behaviour exist in military units. Orders must be clear, with clear instructions on what is to be done, how and what constraints apply. Careful and complete briefing of troops being deployed to a peacekeeping operation is required in order to ensure that cultural misunderstandings do not lead to frustration, stress and unacceptable behaviour. The effects of media coverage, including own media operations, on the behaviour and expectations of military units must be analysed and carefully considered, especially in those operations where there are limits on how units can carry out their mission. The report also recommends further studies into three key areas. The first is leadership and how this is affected by group identity and group values. The second key area is what level of humiliation and perceived threat to self-worth and group values is sufficient to trigger hostile aggression, and whether repeated but minor humiliations are sufficient to cause enough cumulative stress to trigger hostile aggression against others. The third key area is whether it is possible to develop methods to identify operations and situations which can lead to negative stress and the risk of misconduct and, based on this, the development of suitable mitigation measures to reduce the likelihood of misconduct.