Abstract
The Sexual Homicide Crime Scene Rating Scale for Sexual Sadism (SADSEX-SH) is a rating scale which dimensionally measures the degree of offender sexual sadism in suspected sexual homicide cases. Scoring is accomplished using crime scene and related investigative information. Preliminary norms for the SADSEX-SH prototype indicate that it correctly classified offenders with and without sexual sadism. This study further assessed SADSEX-SH sensitivity, specificity, and inter-rater reliability by comparing a larger sample of male sexual homicide offenders with (n = 20) and without (n = 20) sexual sadism. Two items generally undetectable at crime scenes were removed from the originally proposed 10-item scale, resulting in a final 8-item version. SADSEX-SH total scores for the two groups significantly differed (7.7 ± 3.5, range = 2-14 vs. 2.6 ± 2.0, range = 0-7, t = 5.58, p < .001). Inter-rater reliability was excellent (intraclass correlation coefficients [ICCs] = 0.6-1.0). Using a revised cutoff score of 6, sensitivity was 70.0% and specificity was 90%. This revised scale may prove useful for investigators, clinicians, and institutional professionals in helping to identify and address sexual sadism in sexual homicide offenders.
Introduction
Research efforts in the forensic sciences have continued to slowly but steadily advance our understanding of how sexual homicide offender’s psychiatric and personality characteristics can influence crime scene actions (Beauregard & DeLisi, 2018; Chan, Beauregard, & Myers, 2015; Chan & Heide, 2009; MacCulloch, Snowden, Wood, & Mills, 1983; Myers & Blashfield, 1997). Although the findings from such studies will rarely if ever allow a crime to be solved independent of old-fashioned detective work, they can help investigators narrow their leads and focus their energies when developing and investigating possible suspects. Research data that can assist in solving homicides is timely: Murder clearance rates have continued to decline since the 1960s, and in 2016, only 59% of homicides were cleared (Federal Bureau of Investigation, 2017). Furthermore, sexual homicide clearance rates are believed to be even lower, in part because they more often involve stranger victims, are less likely to be witnessed, are commonly driven by less discernible motives, and tend to involve more planning when compared with usual murders (Reale, Beauregard, & Martineau, 2017; Skott, Beauregard, & Darjee, 2018; Wellford & Cronin, 1999).
One of the more obvious indicators of mental aberration exhibited at sexual murder crime scenes is the physical expression of sexual sadism. Sexual sadism is defined by the American Psychiatric Association’s (APA) Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5; APA, 2013) as a condition in which a person has “recurrent and intense sexual arousal from the physical or psychological suffering of another person, as manifested by fantasies, urges, or behaviors” (APA, 2013). The concept, case descriptions, and criminal manifestations of sexual sadism have been remarkably stable over the years, ever since it was officially named and meticulously described in the 19th century by Krafft-Ebing (1898/1965). This phenomenological consistency for over a century is demonstrated, for instance, by case descriptions in Sadism and Masochism: The Psychology of Hatred and Cruelty (Stekel, 1929); in the similar iterations of Diagnostic and Statistical Manual of Mental Disorders (DSM) sexual sadism since Diagnostic and Statistical Manual of Mental Disorders (3rd ed.; DSM-III; APA, 1980); the sexually sadistic behaviors of serial murderers reported by Dietz, Hazelwood, and Warren (1990); Marshall and Hucker’s (2006) 17-item set of behavioral criteria they believed were most relevant for the diagnosis of sexual sadism; and the features of Severe Sexual Sadism Scale (SSSS), an 11-item screening device for the file-based assessment of forensically relevant sexual sadism in sexual offenders (Mokros, Schilling, Eher, & Nitschke, 2012; Nitschke, Osterheider, & Mokros, 2009).
Thus, investigators who can reasonably conclude from crime scene analyses that their sexual homicide suspects have sexual sadism can be armed with this knowledge and on the lookout for associated signs of the condition as they conduct background investigations and interviews. For example, the as yet unidentified perpetrator may have a criminal history of sexual aggression and/or evidence of sexually sadistic interests as revealed by neighbors, friends, intimate partners, coworkers, computer activities, reading or writing materials, photographs, art interests, other lifestyle habits, and even their tattoos (Dietz, Harry, & Hazelwood, 1986; Hazelwood, Warren, & Dietz, 1993; Seto, Lalumière, Harris, & Chivers, 2012).
SADSEX-SH: Sexual Homicide Crime Scene Rating Scale for Sexual Sadism
The SADSEX-SH was preliminarily designed as a 10-item rating scale to dimensionally measure the degree of offender sexual sadism expressed at sexual homicide crime scenes (see Jones, Chan, Myers, & Heide, 2013). The SADSEX-SH is unique in that it aims to assist in the diagnostic assessment of unidentified or unconfirmed perpetrators purely from crime scene actions and findings, that is, unlike scales that rely on post-conviction offender interviews and institutional file data. It was constructed based on the sexual sadism and sexual homicide literature combined with the empirical experience of the authors in evaluating sexually sadistic murderers and sexual homicide crime scene characteristics (e.g., Brittain, 1970; Chan & Heide, 2009; Chan et al., 2015; Dietz et al., 1990; Federoff, 2008; Gratzer & Bradford, 1995; Healey, Lussier, & Beauregard, 2012; Marshall, Kennedy, & Yates, 2002; Myers, Chan, & Damiani, 2016; Myers, Chan, Justen, & Lazarou, 2009; Nitschke et al., 2009). Preliminary norms for the 10-item SADSEX-SH prototype indicated it showed promise in predicting offender sexual sadism in sexual homicides. Five adult male sexual murderers with the diagnosis of Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR; APA, 2000) sexual sadism who had killed adult females were randomly selected from author case files and then matched with five male adult sexual murderers without sexual sadism who also had killed adult females. Both groups were then rated using the SADSEX-SH prototype. Comparisons made on basic demographic variables found no significant differences based on age at the time of the murder, race, or IQ. Using a preliminary cutoff score of 8, all 10 individuals were correctly identified as having sexual sadism or not (Jones et al., 2013).
The present study was undertaken to further assess the sensitivity, specificity, predictive value, and inter-rater reliability of the SADSEX-SH by comparing a larger, more representative sample of male sexual homicide offenders with (n = 20) and without (n = 20) sexual sadism using the clinical diagnosis of sexual sadism based on DSM-IV-TR. Based on the authors’ ongoing practical experience with the SADSEX-SH prototype, it was decided that two of the original 10 items—sadistic fantasy and sexual excitement—would be dropped given the inherent difficulty in reliably confirming or negating their presence at crime scenes to score the SADSEX-SH. Therefore, in this study, the finalized 8-item SADSEX-SH version was examined (see Table 1).
SADSEX-SH Rating Scale.
Note. Scoring: Not present or unknown = 0 point, possibly present/some evidence = 1 point, present = 2 points. SADSEX-SH = Sexual Homicide Crime Scene Rating Scale for Sexual Sadism.
Method
Subjects
Subjects were 40 convicted adult male sexual homicide offenders with (n = 20) and without (n = 20) sexual sadism who had killed adult female victims. Twenty subjects were from a U.S. sample and 20 were from a Canadian sample. All 40 of these cases met the definition for sexual homicide as provided by Chan (2015) as well as Ressler, Burgess, and Douglas (1988).
For the U.S. sample, 15 of the offenders were from author cases that were obtained during forensic psychiatry consultation and which had ultimately become part of the public domain as their criminal cases proceeded through the legal system. These 15 cases were supplemented by five detailed case reports from the sexual homicide literature to reach a number of 20 for the U.S. group (Geberth, 2010; Leach & Meloy, 1999; Reavis, 2011; Ressler et al., 1988; Wilber, 1985). The Canadian sample was identified by author E.B. from a large database compiled during a prospective study on the recidivism of sex offenders. This database included 624 cases, of which 85 were sexual homicides (see Beauregard & Proulx, 2002, for additional information on this database). During the above process, the two final U.S. and Canadian samples were matched for DSM-IV-TR sexual sadism such that this disorder was present in 50% of both.
Each of the samples was diagnosed using DSM-IV-TR criteria, extensive clinical interviews, and all available case and file information. Demographic information for the samples is shown in Table 2, and as can be seen, the groups were also matched on age but differed in race and educational level (see Table 2). None of the subjects in the U.S. and Canadian samples had psychotic disorders or intellectual disability.
Sociodemographic Characteristics.
Measures and Procedure
The finalized 8-item SADSEX-SH was applied to the sample cases using crime scene and any other available investigative information (e.g., scene photos, autopsy results, laboratory confirmation of the presence of semen). SADSEX-SH items were scored as criterion not present (0), possibly present/some evidence (1), or present (2) (score range = 0-16). Any given crime scene data point was not used to support more than one SADSEX-SH criterion; if an item conceivably could have applied to two different criteria (e.g., gratuitous violence [#4] and sexual mutilation [#7]), then only the one it most closely fits was scored. All SADSEX-SH ratings were completed by the first two authors and third author ratings were used for inter-rater reliability. Inter-rater reliability was excellent (intraclass correlation coefficients [ICCs] = 0.6-1.0).
Sexual Homicide Crime Scene Case Study/Scoring Example
A middle-aged female store owner did not return home after work. The police were called and found the store locked and dark. They looked through the window and saw a what appeared to be a body on the floor. They made entry and found a naked, beheaded victim (Criterion #4: score = 2) on her back in a spread-eagle pose. Her clothes evidently had been shredded, perhaps with a knife, were scattered about, and only minimal blood was visible on them (Criterion #1: score = 2). Numerous, scattered stab wounds were visible about her torso and neck areas (Criterion #4: score = 2). Extensive bleeding had occurred and there was blood spatter on the nearby walls. Upon further inspection, the officers observed that her genital region had seemingly been dissected out (Criterion #7: score = 2) and could not be located (Criterion #8: score = 2).
The SADSEX-SH score for this crime scene was 8, indicating the murderer likely had a diagnosis of sexual sadism. The perpetrator was eventually apprehended, and investigators learned he had a notable history of sexually sadistic behavior with females—both partners and acquaintances. Although he previously had been arrested for his sexually sadistic behaviors, he was never convicted of a sex crime. With time, he also became a person of interest in another murder.
Results
The finalized 8-item SADSEX-SH version applied in the current study continued to show acceptable psychometric properties when evaluated using a larger, more representative sample from two countries. There was a significant difference on resulting SADSEX-SH total scores for those offenders with and without sexual sadism (7.7 ± 3.5, range = 2-14 vs. 2.6 ± 2.0, range = 0-7, t = 5.58, p < .001). Using the revised cutoff score of 6, the sensitivity, specificity, and predictive values of the SADSEX-SH were as follows: sensitivity = 70.0%, specificity = 90%, positive predictive value = 88%, and negative predictive value = 79%, and area under the curve = .813. Alternative higher and lower cutoff scores were considered but they resulted in a notably less salutary balance of sensitivity and specificity.
Discussion
To the authors’ knowledge, the SADSEX-SH is the only crime scene rating scale that has been designed specifically to assess for the presence of sexual sadism in unidentified or unconfirmed sexual homicide offenders. In this expanded study, which supplemented a U.S. sample with a similar offender group from Canada, the sensitivity, specificity, and predictive values of the SADSEX-SH remained encouraging. The SADSEX-SH continued to demonstrate a reasonable ability in classifying offenders as to whether or not they had sexual sadism based on crime scene and related information. Perhaps, most importantly, the positive predictive value was 88%, meaning a SADSEX-SH score of 6 or greater was able to correctly identify approximately nine out of 10 sexually sadistic offenders.
These findings further suggest that the SADSEX-SH-R has potential for application in law enforcement investigation, forensic assessment of criminal defendants, violence risk assessment, and prisoner disposition and treatment considerations. Criminal defendants accused of sexually sadistic killings not uncommonly downplay the extent of their deviant interests and behaviors (Dietz et al., 1990; Leitenberg & Henning, 1995; Myers, 2004). A tool that can help discern if they have sexual sadism may provide important supplementary information in determining motivation, degree of culpability, correctional institution placement and management, and dispositional planning. Moreover, the diagnosis of sexual sadism has been implicated as a risk factor for future sexual offenses (Kingston, Seto, Firestone, & Bradford, 2010; Myers et al., 2009; Ressler et al., 1988). Institutions and correctional professionals having this diagnostic information, which needs to have been corroborated by clinical interview(s) and a comprehensive review of all relevant case materials, can help inform institutional treatment approaches from an individual, group, educational, vocational, and pharmacological standpoint (Briken, Bourget, & Dufour, 2014; Firestone, Bradford, Greenberg, & Larose, 1998). An example of how this information can be vital is brought out by the case of a convicted murderer and sexual sadist evaluated by author W.M. who was given increasing amounts freedom in his institution after several years of no violent behavior. He ultimately attempted to sexually assault a female staff member and then sadistically killed a male inmate.
There are several limitations to this study. First, it only considered murderers with adult female victims. How the SADSEX-SH might perform with other types of sexual homicide, for example, murders involving male or child victims, remains to be explored. Second, the study sample was limited to North American offenders, and therefore, the generalizability of the findings to other geographic regions has not been tested. Theoretically, the phenotypic expression of sexual sadism is going to be similar from one country or culture to the next, but this assertion has not been rigorously examined. Third, the U.S. and Canadian samples were able to be matched on sexual sadism diagnosis and age but differed on race and educational level. This is likely a reflection of the different demographic pools from which they came. While the authors do not expect that this imbalance in race and education had a marked influence on the study findings, it nonetheless would have been preferable to have the samples matched on all characteristics. Fourth, larger samples with broader geographical representation ideally are needed to allow a more in-depth look at the usefulness of the SADSEX-SH. Fifth, it is conceivable that a particularly gruesome crime, even though committed by an offender entirely free of sexual sadism, might result in an elevated SADSEX-SH score. For instance, a killing committed by a severely intoxicated or psychotic individual who involved dismemberment and removal of trivial items from the home might erroneously be interpreted as having features of a sexually sadistic homicide. However, the gratuitous violence and taking of “souvenirs” in such a scenario could have been brought about solely by confused and/or delusional thinking.
The SADSEX-SH is a novel tool that aims to help to identify sexually sadistic killers. Moreover, the fact that the scale is entirely based on crime scene characteristics and associated findings allows it to serve as a complementary source of information that can be applied in subsequent clinical settings, for example, during diagnostic and treatment assessments. Offenders with sexual sadism not uncommonly attempt to hide or downplay their condition, so corroborative data may prove helpful. The SADSEX-SH also can potentially contribute to our understanding of the concept of sexual sadism as it relates to the law enforcement realm. For instance, a study by Reale et al. (2017) has shown that sadistic sexual murderers were more likely to use various precautions to avoid detection and select a deserted location when compared with non-sadistic offenders. In addition, the findings showed that sadistic sexual murderers were more likely to avoid detection and have their case remain unsolved. Examining crime scene correlates of sexual sadism—especially those that are easily observable at the crime scene—may not only help with the identification of such offenders but also contribute to our understanding of the more extreme expressions of this disorder. This is especially important for law enforcement and public safety, as violent sexually sadistic offenders are believed to be at a considerably elevated risk for recidivism (Berner et al., 2003).
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
