Introduction

Considerable evidence exists to suggest that the majority of crime is committed by a minority of repeat offenders (for example, Clarke and Eck, 2003; Tilley and Laycock, 2002), with this trend holding for a variety of offence types, including sexual offending (for example, Woodhams and Labuschagne, 2012). Apprehending these prolific offenders at the earliest opportunity is vital if society is to be protected from the significant financial and psychological consequences of their crimes (for example, Peterson et al, 2017; Santiago et al, 1985). Behavioural crime linkage (BCL) is one technique utilised by law enforcement agencies across the world to tackle serial offending, including serial sexual offending (Woodhams et al, 2007a). BCL involves a detailed analysis of offender crime scene behaviour, with the aim of identifying groups of crimes that share similar (and distinctive) offender behaviours that allows the police to ‘link’ the crimes as a series and to infer that the same person (or persons) were responsible for the crimes (Woodhams and Bennell, 2015a).

Successful crime linkage can increase the quantity and quality of evidence available to the police (Ashmore-Hills et al, 2017), which increases the likelihood of apprehending and successfully prosecuting repeat offenders (Grubin et al, 2001). This allows victims greater access to justice (thereby helping to repair the damage caused, at least to some extent) and prevents these offenders from continuing to offend against the public (at least while they are incarcerated). As such, BCL offers both primary and secondary prevention against the damage caused by prolific, repeat offenders. Linking crimes can also save the police time and money, as it streamlines the investigative process (Santtila et al, 2005), avoiding the duplication of roles, responsibilities, and work (Woodhams et al, 2007b). Both benefits are extremely valuable at a time when police-recorded sexual offending is at record levels (Office for National Statistics, 2018) and resources available are limited (Ashmore-Hills et al, 2017).

This chapter will explain the theoretical framework underpinning BCL (behavioural consistency and behavioural distinctiveness) and summarise the research that has tested whether sexual offenders behave in a consistent and distinctive way when offending. Furthermore, the chapter will examine how researchers have tried to statistically and methodologically capture information about sexual offending behaviour and use that information to underpin more accurate and efficient strategies for preventing sexual violence through BCL.