Is behavioural profiling a viable alternative to more traditional approaches to profiling, viewed from the perspectives of underlying theoretical assumptions and measures of effectiveness? In this article we describe behaviour profiling in relation to other types of profiling, we review relevant psychological mechanisms that underpin behaviour profiling, and discuss effectiveness of this type of profiling as well as methodological aspects of measuring effectiveness. Behaviour profiling is a method largely used to select potential offenders before the offence is committed by observing and giving meaning to behaviours preceding incidents. Deviant behaviours exhibited by suspects can be either part of a modus operandi related to the offence, the consequence of increased stress, or an atypical response to prodding actions by security officers. Relevant psychological mechanisms to explain ways behaviour profiling works include direct characteristics of deception as well as indirect indicators of deception, such as a criminal being more self-focused and more cognitively engaged. Effectiveness of behaviour profiling is increased by training, including learning more about modi operandi and related behaviours, awareness of biases in general, specific relevant biases, and techniques to correct for these biases.

This article is about the ability of human beings to make a deliberate choice to do evil. Punishing evildoers according to penal law presupposes that they are responsible for their acts, i.e. that they acted out of free will. In the first part I recall the origins of the classical nexus between free will, responsibility and punishment in Christian theology and scholastic philosophy. Then I analyze the philosophies of Sade and Nietzsche in order to demonstrate how the traditional conception of good and evil can be inverted. Sades extreme moral relativism and Nietzsches radical perspectivism open the gates for a justification of moral evil. In the final part I look at the serial killer as an actor who deliberately chooses to do evil. The personality disorder (psychopathy) of most serial killers probably affects their inhibition to harm others. But although their lack of empathy can lower the threshold for harming others, this (mostly) does not annihilate their moral responsibility. Such can be exemplified by the fact that many serial killers are acting in an extremely strategic, opportunistic and deceitful way in order to ensure the persistence of their deliberate choice to do evil. Moreover, some serial killers, when justifying their behavior, engage in arguments putting into perspective ‘good’ and ‘evil’ in a way that is reminiscent of Sade and Nietzsche.