The Problem of Definition and Terms

In the FBI’s Uniform Crime Reports (UCR), which provides annual summaries of crime statistics, homicide is defined as the willful (nonnegligent) killing of one human being by another. Deaths caused by negligence, accidents, suicide, or justifiable homicides are not categorized as murder. The level of intent (as in the legal system’s classification of homicide into first-degree and second-degree murder, manslaughter, etc.) is also not considered. The UCR definition, which is based on findings reported by police investigators, is reasonably clear-cut. It does not take into account an offender’s internal state or such issues as blame or moral responsibility. These matters, which are difficult to assess objectively, are left to lawyers, judges, mental health experts, and jurors.

The definition of sexual homicide, on the other hand, is not at all clear-cut. Sexual homicide is not defined by statute as are the illegal paraphilias (such as pedophilia) and

Table 1.1 Problems Encountered in the Study of Sexual Murder

other sex crimes (such as rape), and the Diagnostic and Statistical Manual of Mental Disorders (in any of its editions) has never defined sexual homicide as a specific paraphilia, nor has the International Classification of Diseases. Moreover, inherent in the definition of sexual murder is the issue of intent, which adds to the definitional problems. For example, Ressler, Burgess, and Douglas (1988) generally define sexual homicide as “the killing of a person in the context of power, sexuality, and brutality” (p. 1). Almost all killings, however, involve some degree of power and brutality. How do these characteristics distinguish a sexual homicide from a nonsexual homicide? And what is the meaning of “sexuality” in this definition? Does it refer to actual sexual behavior? To render the killing a sexual murder, must there be intercourse, attempted intercourse, a desire for intercourse, or just an internal feeling of arousal? How can an investigator determine whether an offender’s arousal was sexual arousal or merely a general arousal (a heightened emotional state) felt by someone who has committed a crime and risks apprehension? In many cases, a clinician will decide that a murder is a sexual murder because it appears to be a sexual murder (Prentky et al., 1989; Swigert, Farrell, and Yoels, 1976). But what appears to be a sexual murder to one practitioner may appear otherwise to someone else.

Along with differences in definitions, many different terms have been used to describe sexual murder, including lust murder (Krafft-Ebing, 1886), sadistic lust murder (De River, 1958), sadistic murder (Brittain, 1970), lust killing (Malmquist, 1996), and even erotophonophilia (Money, 1990), among others (see Table 1.2). Sometimes the same term, such as lust murder, is defined differently by different authors (Hazelwood and Douglas, 1980; Krafft-Ebing, 1886). Reid (2017a) has documented 43 different conceptualizations of sexual and serial murder, some operationalized and some vague descriptions of behavior. Greenall (2012) has described four different scenarios that could define a sexual homicide. Kerr, Beech, and Murphy (2013) listed 13 different definitions of sexual murder. Higgs, Carter, Tully, and Browne (2017) reviewed empirical studies of sexual murder between 1970 and 2016 and reported three types of offenses: “sexualized murder” involving sadism, “grievance murder” involving anger, and “rape murder.” While all of these definitions and approaches have merit, the issue of what constitutes a sexual murder remains unsettled.

Many, but not all, researchers agree that serial murders are sexual murders with multiple victims (Schlesinger, 2000a). Some define serial murder as literally the killing of multiple individuals, rather than viewing the crime more narrowly as a subtype of sexual murder (Egger, 1990a). For example, Dietz (1986) distinguishes five separate types of serial murderers: psychopathic sexual sadists, crime spree killers, organized crime multiple murderers, custodial prisoners and serial asphyxiators, and supposed psychotics

who kill multiple victims. Only the first type is sexually motivated. In an attempt to add definitional precision, Jenkins (1988, 1989) specifically excludes politically motivated and professional contract killers, thereby adhering more to the traditional sexual view of serial murder. The FBI (Morton and Hilts, 2005) recently updated their definition of serial murder to include two or more victims, in separate events at different times. The term “spree murder” (involving a cooling-off period between murders) was essentially eliminated as a separate category.

These differences in terminology and definitions, although they often make communication regarding the meaning of findings difficult, are to be expected in the developing stages of scientific inquiry.