Whiter Than White: The Art of Delaying Detection in Sexual Killers

The study investigated whether different types of sexual homicide perpetrators are more or less skilled at delaying detection. Using the newly proposed direct/indirect typology, the time of arrest, the frequency of specific precautions as well as the impact of forensic strategies used by the perpetrators were examined. The results indicated that the time from the killing to the arrest, as measured in days, was longer for the direct than the indirect sexual killers. Despite the fact that the direct aggressors were better at delaying detection, overall the indirect and the direct offenders did not differ in the frequency of use of most of the precautions. However, different forensic awareness strategies were more efficacious for the direct and the indirect offenders. These results are discussed in relation to the crime scripts for the two perpetrator groups

Sadism among sexual homicide offenders:Validation of the Sexual Sadism Scale

Sexual sadism is assumed to be a crucial factor in sexual homicide. Prevalence estimates vary greatly due to differences in the definition of sexual sadism. A nationwide sample of 350 male perpetrators who had committed a sexual homicide offense against a female 14 years of age or above in England or Wales was assessed based on archival records. Sexual sadism was assessed using the Sexual Sadism Scale (SeSaS). Item response theory (IRT) analyses were conducted focusing on the 2-parameter logistic model. The single-factor structure of the SeSaS Part 1 was tested using confirmatory factor analysis. Estimates of both internal consistency and interrater agreement were satisfactory to substantial. IRT analysis showed that the Part 1 items captured moderate to severe levels of the latent construct (i.e., theta levels >0). Based on the Posterior Probability of Diagnosis index, the prevalence of the disorder was estimated at 37% in the sample. The substantial correlation between the SeSaS Part 1 total score and original clinical diagnoses of sadism confirms the criterion validity of the scale. Exertion of control and infliction of torture were among the more informative items. In sum, the results support the usefulness of the SeSaS instrument for assessing forensically relevant forms of sadism

The developmental and criminal histories of subgroups of sexual murderers engaging, or not engaging, in post mortem sexual interference, compared to rapists

Purpose Identifying factors that may predict sexual aggression in the context of directly sexual murder, indirectly sexual murder, and non-fatal outcomes is necessary for advancing a field lacking a substantiated multifactorial theoretical model. Methods Eighty-nine sexual murderers engaging in post mortem sexual interference were compared to 92 non-post mortem sexual interference sexual murderers and 72 rapists on developmental factors, adult lifestyle, and criminal history. An overall model was built using a series of multinomial logistic regression analyses. Results Unlike rapists, both groups of sexual murderers experienced a lack of success in sexually intimate relationships. Perpetrators of post mortem sexual interference were rarely necrophiles, but having a history of sadistic behaviors or interests uniquely predicted sexual murder involving post mortem sexual interference. Chronic violent and sexual offending was characteristic of rapists. Psychopathy, measured using the screening version of the Psychopathy Checklist (Hart, Cox, & Hare, 1995), was not predictive of any outcome. Conclusion Results support criticism of existing theoretical models; that they do not apply to non-sadistic sexual murder. Findings are discussed in relation to gaps in theoretical understanding of sexual murder, and concerning implications for forensic policies and practice

Our love was a two-person game. At least until one of us died, and the other became a murderer: sexual homicide perpetrated by intimate partners

Purpose: The analysis of previous studies showed that research pertaining to the examination of the crime scene and Modus Operandi variables in intimate partner homicide (IPH) is scarce. Additionally, to our knowledge, there are no studies investigating sexual homicide perpetrated by intimate partners. This study aims to address that void. Thus, the study examined various components of the crime event and as such, it was exploratory in nature. Design/methodology/approach: The study consisted of male sexual killers, who perpetrated against pubescent female victims (14 years old and over) and served a custodial sentence within Her Majesty’s Prison Service in England and Wales. Variables for the study were chosen on the basis of previous research examining IPH and sexual homicide. Descriptive analyses were used in this exploratory study. Findings: Descriptive analyses indicated that the most prevalent aggravating circumstances in the lead up to the killing included conflict with the victim before the offence and substance use by the perpetrator around the time of the killing. Stalking was present in approximately a quarter of cases. The results of the analyses of sexual behaviours showed that in 54.9% of the sample the act of killing was purely instrumental whereas in 39.4% of the sample the underlying drive of the act of killing was closely related to the sexual aspect. Originality/Value: This is a unique study on a topic not yet explored

A systematic review of the literature comparing male non-serial sexual killers and sexual aggressors: examining homogeneous and heterogeneous characteristics of these groups

This systematic review considers what is known about the characteristics of sexual killers and sexual aggressors. The aim was to identify which characteristics have consistently been shown to be similar (homogeneous) and which are different (heterogeneous) across these two groups. Ten studies, including approximately 300 sexual killers, were analysed. Only studies where the samples were directly compared and where sexual killers were male, predominantly non-serial and perpetrated against adult female victims were included. Results indicate that levels of loneliness and anger appear to be more prevalent in the sexual killer sample while mental health disorders, criminal history, family structure and history of sexual abuse as well as some crime scene behaviours seem to be similar across the two groups. The results of this review have also highlighted some methodological problems inherent to these types of studies and these issues are discussed from the perspective of improving research on these crimes

Investigating the influence of Fe speciation on N2O decomposition over Fe–ZSM-5 catalysts

The influence of Fe speciation on the decomposition rates of N2O over Fe–ZSM-5 catalysts prepared by Chemical Vapour Impregnation were investigated. Various weight loadings of Fe–ZSM-5 catalysts were prepared from the parent zeolite H-ZSM-5 with a Si:Al ratio of 23 or 30. The effect of Si:Al ratio and Fe weight loading was initially investigated before focussing on a single weight loading and the effects of acid washing on catalyst activity and iron speciation. UV/Vis spectroscopy, surface area analysis, XPS and ICP-OES of the acid washed catalysts indicated a reduction of ca. 60% of Fe loading when compared to the parent catalyst with a 0.4 wt% Fe loading. The TOF of N2O decomposition at 600 °C improved to 3.99 × 103 s−1 over the acid washed catalyst which had a weight loading of 0.16%, in contrast, the parent catalyst had a TOF of 1.60 × 103 s−1. Propane was added to the gas stream to act as a reductant and remove any inhibiting oxygen species that remain on the surface of the catalyst. Comparison of catalysts with relatively high and low Fe loadings achieved comparable levels of N2O decomposition when propane is present. When only N2O is present, low metal loading Fe–ZSM-5 catalysts are not capable of achieving high conversions due to the low proximity of active framework Fe3+ ions and extra-framework ɑ-Fe species, which limits oxygen desorption. Acid washing extracts Fe from these active sites and deposits it on the surface of the catalyst as FexOy, leading to a drop in activity. The Fe species present in the catalyst were identified using UV/Vis spectroscopy and speculate on the active species. We consider high loadings of Fe do not lead to an active catalyst when propane is present due to the formation of FexOy nanoparticles and clusters during catalyst preparation. These are inactive species which lead to a decrease in overall efficiency of the Fe ions and consequentially a lower TOF

“We boil at different degrees”: factors associated with severity of attack in sexual killing

Degree of injury, as measured by the Homicide Injury Scale (HIS), was examined to advance understanding of the dynamics of sexual killing. A total of 350 nonserial, male sexual killers were included, and the different ways that the sexual element of their offenses and the act of killing were connected was accounted for by determining that cases were either directly sexual (the sexual element and killing were closely bound), or indirectly sexual (killing was not a source of sexual stimulation). The two groups, direct and indirect sexual killers, were each subjected to multiple linear regression analyses to examine the group-specific relationship between level of injury and predictor variables previously found to be associated with increased severity of attack. No differences in the mean total HIS scores between the indirect and the direct cases were found, suggesting a comparable emotional intensity between the groups. However, given that the groups differed in terms of the functional role of fatal violence, severity of attack could not be sufficiently explained as driven by anger. In line with this hypothesis, different predictors appeared to be associated with increased degree of injury sustained by victims of indirect compared with direct sexual killers. As such, situational components appear to play a role in the behavior of indirect sexual killers, whereas the behavior of direct perpetrators tends to be linked with the enactment of existing deviant fantasies. The role of anger in sexual homicide is discussed further, and overall, it is argued that irrespective of whether violence was initially driven by anger, evidence of sexual arousal to severe violence must be scrutinized within sexual homicide research as well as in psycholegal contexts

The use of crime scene and demographic information in the identification of non-serial sexual homicide

As with other sexual offenders, sexual homicide perpetrators can be reluctant to talk about their criminal behavior. Therefore, in homicide cases, forensic practitioners frequently rely on crime scene information to identify any sexual behavior associated with the offense. This study aims to identify objective and readily available crime scene information, alongside information about victims and perpetrators, based on 65 cases from England and Wales in the United Kingdom of men convicted of homicide who had committed a non-serial sexual homicide and 64 cases of men convicted of homicide where the available evidence indicated that it was a non-serial non-sexual homicide. Chi-square tests and logistic regression were used to analyze the data. There were few differences in terms of demographic information and criminal histories between the two perpetrator groups. There were crime scene indicators supporting the use of Ressler et al.’s definition of sexual homicide. The victims of sexual homicide were generally found in their home with the lower half of the body exposed and with evidence of vaginal sex. Furthermore, extreme injuries and strangulation were more frequent in sexual homicides. Use of weapon was associated with a non-sexual homicide. Victims of sexual homicide were as likely to know the perpetrator as not. Potential benefits of the characteristics reported to investigators and forensic practitioners tasked with identifying sexual homicides are discussed and areas for further research suggested