Linkage analysis: Modus operandi, ritual, and signature in serial sexual crime

This article examines a process of behavioral analysis, referred to as linkage analysis, used in identifying sexual offenses that have been committed by the same offender. This type of analysis examines behavior that is contained in three distinct components of a crime, i.e., the modus operandi (MO) or the “how to” of a crime; the ritual or fantasy-based behaviors for a particular type or series of sexual crimes; the signature or unique combination of behaviors, which suggests that a series of crimes has been perpetrated by the same offender. Linkage analysis involves five assessment procedures: (1) gathering detailed, varied, and multisource documentation; (2) reviewing the documentation and identifying significant features of each crime individually across the series; (3) classifying the significant features of the crime as either MO and/or ritualistic constructs; (4) comparing the combination of MO and ritualistic features across the crimes to determine if a signature exists; (5) compiling a written analysis that details the conclusions derived from the available information. Results of this type of analysis can be used for investigative purposes and, in some instances, can help to inform the decision-making of the courts.