Although the potential usefulness of the offence action–offender characteristic (A–C) relationships is widely accepted and operational ‘offender profiling’ units now exist around the world, few such relationships have been empirically established. To explore this, the offending action patterns within 111 sexual assault cases from South Korea were coded in terms of 16 distinctive, objective crime scene criteria and subjected to an agglomerative hierarchical cluster analysis. Background psychiatric and general characteristics, Personality Assessment Inventory (PAI) scale scores, and criminal histories were described for each cluster. The cluster analysis drew attention to six clusters or behavioural profiles within the sexual assaults. Cluster 1 included serial offenders who aggressively raped and robbed adult women, with some pseudo‐intimate sexual behaviour, in their homes. Two thirds of these offenders had histories of sexual assault. Cluster 2 included offenders who again targeted adults in their homes, but without pseudo‐intimate sexual behaviour. Cluster 3 included offenders who targeted adults outdoors at night. These offenders showed high antisocial personality PAI scores and psychiatric histories of sexual sadism. Cluster 4 included unarmed offenders who targeted adults in their homes without robbery. These offenders often had psychiatric histories of depression. Cluster 5 included offenders who targeted adults outdoors with a blitz‐style attack, and Cluster 6 included offenders who targeted minors outdoors, without weapons, using a confidence‐trick style of approach. Paedophilia and histories of psychiatric treatment were prominent amongst these offenders. The results indicate therefore some of the key empirical relationships that future research may develop as the basis for sexual assault ‘profiles’. Copyright © 2014 John Wiley & Sons, Ltd.