Sexual Assault

This chapter examines sexual assault as both an individual crime and a pattern of repeat offending that can be detected through the systematic analysis of offender behavior. While forensic evidence from sexual assault kits remains the most reliable method for linking cases, behavioral variables – such as victim selection, approach method, type and timing of force, assault conduct, and post-assault actions – are critical for identifying related incidents when physical evidence is limited or absent. Research indicates that a substantial proportion of sexual assaults are committed by repeat offenders, underscoring the need for proactive behavioral linkage. The chapter outlines how offenders plan and execute attacks, adapt their modus operandi (MO) over time, and occasionally display unique “signature” behaviors that provide investigative leads. It also highlights the importance of recognizing precursor behaviors – such as attempted assaults or surveillance – and of cross-jurisdictional intelligence sharing, including the use of national databases like the FBI’s ViCAP. By integrating behavioral analysis with forensic and geographic data, investigators can more effectively identify serial offenders, prevent additional crimes, and allocate resources to the highest-risk areas.