In the analysis of criminal behaviour, a combination of biological, psychological and social aspects may be taken into account. Dynamical modelling methods developed in recent years often address these aspects separately. This paper contributes an agent-based modelling approach for behaviour of a certain criminal type, the violent psychopath, in which these aspects are integrated in one dynamical system. It is shown how within a certain social context, an interaction between biological factors and cognitive and emotional factors can lead to a crime committed when an opportunity is perceived.