Is the Sexual Murderer a Unique Type of Offender? A Typology of Violent Sexual Offenders Using Crime Scene Behaviors

Interactions Between Offender and Crime Characteristics Leading to a Lethal Outcome in Cases of Sexually-Motivated Abductions

Despite the widespread public concern regarding abduction, research on this type of crime is scarce. This lack of research is even more pronounced when looking at cases that end with the death of the victim. In fact, all of the research looking at lethal outcomes in cases of abductions has focused exclusively on child victims and has failed to consider the interactions at the multivariate level between the factors related to the death of the victim. Therefore, the aim of the study is to identify offender and crime characteristics - as well as their interactions - associated with a lethal outcome in sexually-motivated abductions using a combination of logistic regression and neural network analyses on a sample of 281 cases (81 cases ending with a lethal outcome, random sample of 200 comparison cases). Findings show that sexually-motivated abductions ending with a lethal outcome are more likely to be characterized by an offender who is a loner, forensically aware, and who who uses a weapon and restraints, and who sexually penetrates and beats a known victim. The neural network analysis show that three different pathways lead to a lethal outcome in sexually-motivated abductions. Such findings are important for correctional practices.

Counting the days: Exploring the post-mortem interval factors in sexual homicides

This study explores the offender, victim, and environmental characteristics that significantly influence the number of days a sexual homicide victim remains undiscovered. Utilizing a sample of 269 cases from the Homicide Investigation Tracking System database an in-depth analysis was conducted to unveil the factors contributing to the delay in the discovery of victims' bodies. The methodological approach involves applying a negative binomial regression analysis, which allows for the examination of count data, specifically addressing the over-dispersion and excess zeros in the dependent variable - the number of days until the victim is found. The findings reveal that certain offender characteristics, victim traits, and spatio-temporal factors play a pivotal role in the time lag experienced in locating the bodies of homicide victims. These findings have crucial implications for investigative efforts in homicide cases, offering valuable insights that can inform and enhance the efficacy and efficiency of future investigative procedures and strategies.

Understanding sexual homicide in Korea using machine learning algorithms

The current study was conducted to confirm the characteristics in sexual homicide and to explore variables that effectively differentiate sexual homicide and nonsexual homicide. Further, newer methods that have received attention in criminology, such as the machine learning method, were used to explore the ideal algorithm for classifying sexual homicide and patterns for sexual homicide in Korea. To do this, 542 homicide cases were analyzed utilizing eight algorithms, and the classification performance of each algorithm was analyzed along with the importance of variables. The results of the analysis revealed that the Naive Bayes, K-Nearest Neighbors, and RF algorithms demonstrate good classification accuracy, and generally, factors such as relationships, marriage, planning, personal weapons, and overkill were identified as crucial variables that distinguish sexual homicide in Korea. In addition, the crime scene information of the crime occurring in the dark (at night) and body disposal were found to have high importance. The current study proposes ways to enhance the efficacy of crime investigation and advance the research on sexual homicides in Korea through a more scientific understanding of sexual homicide that has not been thoroughly explored domestically.

Latent profiles identified from psychological test data for people convicted of sexual offences in the UK

BACKGROUND

One size does not fit all in assessment and intervention for people with convictions for sexual offences. Crime scene indicators and risk-related variables have been used to identify distinct clusters of people with convictions for sexual offences, but there is a need for more robust typologies that identify clusters based on psychologically meaningful risk factors that can be targeted in treatment.

AIMS

To use robust modelling techniques to identify latent profiles of people with convictions for sexual offences based on indicators of dynamic risk.

METHOD

Adult male participants, who had been convicted for sexual offences and assessed for eligibility for the prison-based Core Sex Offender Treatment Programme delivered by His Majesty's Prison and Probation Service (UK), were randomly allocated to a test (n = 1577: 70.2%) or validation (n = 668: 29.8%) data-set. Exploratory factor analysis (EFA) was used to select measures of dynamic risk from psychological test data. EFA indicated four factors, from which six measures were selected for inclusion in latent profile analysis.

RESULTS

Five latent profiles were identified in the test and validation data-sets. These were labelled low psychological impairment, impulsive, distorted thinker, rape preoccupied and child fantasist. Profiles varied in individual characteristics, offence histories, victim preferences and level of risk.

CONCLUSIONS

Our findings should be used to guide assessment and intervention practices that are tailored to distinct psychological profiles consistent with principles of risk, need and responsivity.

Characteristics of Sexual Homicide Offenders Focusing on Child Victims: A Review of the Literature

The topic of sexual homicide encompasses various categories of both offender and victim and much research has shown that there are different typologies of sexual homicide offender (SHO). The aim of this study was to review the current literature regarding sexual homicides, with a focus on those SHOs that targeted children. Studies were selected for review based on the samples utilized. Studies that used a mixed sample of sexual homicide, for example, serial/non-serial, adult/child victim, stranger/non-stranger relationship were included, as well as those that exclusively investigated sexual killers of children. Relevant studies were found by utilizing online libraries and databases. Research studies (n = 39) and review studies (n = 3) were deemed suitable to be included in this review. Offender and victim characteristics, as well as crime scene behaviors, offender's previous convictions, psychopathologies and paraphilias were reported. Geographical profiling of sexual homicides was also discussed. The review highlighted the current typologies of SHOs, including the Sadistic/Angry/Opportunistic model and the only current model dedicated to SHOs of children. There are mixed findings within this topic which may be caused by different cultures or different samples. Limitations, such as small sample sizes and the lack of comparison between sub-types of SHOs, were discussed. Suggestions for future research, including further exclusive study of sexual killers of children, were recommended.

Strangulation in sexual homicide: Is it opportunity, victim's vulnerability or sadism?

Although most homicides involve the use of a weapon, some offenders still prefer killing with their own hands, using strangulation. In fact, when disaggregating the various types of homicides, sexual homicide offenders appear as having a preference for "personal weapon" to kill the victim. Personal weapons, such as strangulation, asphyxiation, and beating, are the most commonly used killing methods in sexual homicide. Using a sample of 451 cases of sexual homicide of adult female, the current study examines three hypotheses as to why strangulation is the method of choice to kill in sexual homicide: 1) weapon of opportunity, 2) victim's vulnerability, and 3) sexual sadism. Results from logistic regressions and artificial neural network analysis show that all three hypotheses are supported, sexual homicide offenders using strangulation being less likely to target a victim with a strong build, to bring and use a weapon. However, strangulation is more likely to be used to kill the victim when the offender is characterized with sadism. Implications of the findings are discussed in light of our understanding of the crime-commission process involved in sexual homicide.

Juveniles arrested for murder: A latent class analysis of male offenders

Researchers and practitioners have a need for valid and generalizable typologies of juvenile homicide offenders (JHOs) to better understand the heterogeneous nature of JHOs, and use this knowledge to inform prevention efforts. Prior studies of JHOs have typically utilized a clinical approach, which is rich in data but based on small nonrepresentative samples, or relied on larger aggregate datasets which are more reliable but have few measures available. This study aimed to address these limitations by examining the latent heterogeneity (i.e. unapparent differences) in JHOs, their victims, and incident characteristics among more than 40,000 male JHOs arrested in the United States between 1976 and 2016 using latent class analysis, to allow for the objective identification of latent taxonomies. Six distinct subtypes of male JHOs are found in the analysis, which contributes to the theoretical and substantive knowledge base regarding JHOs, and may be used to develop and implement more effective interventions and violence prevention programs for these young offenders.

Sex worker homicides and sexual homicides: A comparative study of offender, victim, and offense characteristics

Sex workers are commonly claimed to be at heightened risk of fatal victimization. Although prior research indicates that the dynamics of sex worker homicides resemble sexual homicides more than nonsexual homicides, little is known about how these types of homicides compare in terms of offending patterns. This study considers a sample of 2,851 single-victim, single-offender homicide cases extracted from a 37-year (1976-2012) US Supplementary Homicide Reports database, and compares the offender, victim, and offender characteristics of 243 sex worker homicides (189 males and 54 females) with those of 2608 sexual homicides (2474 males and 134 females). The findings suggest that the offender, victim, and offense characteristics of general, male-offender, and female-offender sex worker homicides are essentially different from the characteristics of sexual homicides. Logistic regressions further indicate that most offender, victim, and offense characteristics on the occurrence of general and male-offender sex worker homicides were significantly associated with the perpetration of general and male-offender sex worker homicides, with reference to sexual homicides. These findings offer insights relevant to the prioritization of criminal investigative practices.

Alcohol and drug problems among Australian homicide offenders

BACKGROUND AND AIMS

Most homicide studies focus upon 'acute' situational intoxication as opposed to 'chronic' substance misuse. The aims of the study were to: (1) determine the extent of homicide offenders' alcohol and drug use in the year preceding the homicide; (2) compare the individual characteristics of homicide offenders across levels of problematic substance use; and (3) compare homicide incident characteristics across levels of problematic substance use.

DESIGN AND SETTING

Observational study using data collected through face-to-face interviews in custodial and community correctional settings across Australia. Participants were recruited through an opt-in process.

PARTICIPANTS

The data consist of 302 individuals convicted of murder or manslaughter.

MEASUREMENTS

We used the Alcohol Use Disorder Identification Test and Drug Abuse Screening Test to determine problematic alcohol or drug use. We also used a range of self-report measures to ascertain offender characteristics [socio-demographics, developmental experiences, criminal history, personality] and incident characteristics (who was killed, and situational intoxication).

FINDINGS

Of the sample, 38.8% displayed high levels of alcohol problems and 30.8% displayed high levels of drug problems. Those displaying high levels of alcohol and/or drug problems were more likely than those without high levels of alcohol and/or drug problems to report adverse developmental experiences, low education, financial difficulties, extensive criminal histories and high levels of trait anger, impulsivity and risk-seeking. In addition, offenders with problematic substance use were more likely to have killed non-family and to have used substances at the time of the homicide.

CONCLUSIONS

High proportions of homicide offenders in Australia appear to have problematic substance use in the year preceding the homicide offence, and such use appears to be associated with a range of other challenging factors, including adverse childhoods, criminal involvement, low socio-economic factors and low self-regulation.

Homicidal child sexual abuse: Identifying the combinations of factors predicting a lethal outcome

BACKGROUND

Research on sexual homicide of child victims is scarce. Studies focusing on the lethal outcome in sexual crimes involving adult victims suggest that those offenders who end up killing their victims present both specific individual and crimecommission process characteristics. Nevertheless, recent studies indicate that findings with adult victims may not adequately explain the lethal outcome in sexual crimes of children.

OBJECTIVE

The purpose of this study is to identify specific combination of offenders, victims and crime-commission process factors associated with a lethal outcome in child sexual abuse.

PARTICIPANTS

This study compares and analyzes the characteristics of 646 cases of extrafamilial child abuses with 136 cases of sexual homicide involving children.

METHODS

Bivariate analyses and sequential binomial regression analyses were conducted to identify variables associated with crime outcome. Finally, conjunctive analyses were used to identify combinations of factors that are the most likely associated with the lethal outcome.

RESULTS

Results indicate that both offenders and crime-commission process characteristics are strongly associated with sexual homicides of children.

CONCLUSIONS

Offenders who sexually murder children are extremely instrumental and opportunistic. They are also more likely to have a life history characterized by the manifestation of diverse antisocial conducts. The findings of this study provide important theoretical and practical implications for crime investigations, prevention, and offenders' management.

Coercive Sexual Sadism: a Systematic Qualitative Review

PURPOSE OF REVIEW

Coercive sexual sadism can be distinguished from consensual BDSM (bondage discipline/dominance submission/sadism masochism) role-play and from everyday sadism, a personality trait. The purpose of this paper is to provide a systematic qualitative review of the pertinent literature on coercive sexual sadism from the last three years.

RECENT FINDINGS

Clinical assessment of sexual sadism can be made more objective through behavioral checklists based on crime scene actions. The latent structure of sexual sadism is likely dimensional, placing the disorder at the upper end of a continuum of sexually aggressive behavior. Sexual sadism does not seem to increase the risk of violent offense recidivism (including sexual contact offenses) above and beyond the risk implied by established risk factors of delinquency. Coercive sexual sadism denotes a disposition for sexually aggressive behavior. Whether this disposition is put into practice is likely due to other trait and state variables. Treatment studies are completely lacking in the recent literature.

Sexual Homicide: a Criminological Perspective

PURPOSE OF REVIEW

This review presents recent findings of research focusing on sexual homicide. Firstly, we examine international comparative studies of victim, offender, and crime characteristics. Secondly, we review an important body of literature that compares developmental and psychological as well as the decision-making process of sexual murderers with other violent offenders. Thirdly, recent and major findings on links between sexual homicide and psychopathy as well as sadism are presented. Fourthly, findings on spatial behavior and factors that can explain it are discussed. Finally, the last section reviews characteristics of sexual homicide involving children and elderly victims.

RECENT FINDINGS

International comparisons suggest that sexual homicide presents more similarities than differences across countries implying that most of knowledge can be generalized and applied to other countries. Comparisons with other types of violent offenders highlight that sexual murderers are a specific type of offenders with particular characteristics (criminal careers, developmental factors, personality disorders, lifestyle characteristics) and crime commission process (modus operandi, spatial behavior). As to the etiological factors of sexual homicide, psychopathy and sadism are important characteristics of sexual murderers leading their criminal life as well as their everyday life. Finally, studies focusing on specific types of vulnerable victims showed a high level of heterogeneity within the population of sexual murderers. Sexual murderers are specific offenders with peculiar characteristics and further research should develop proper knowledge on it. Creation of new international databases allows research to confirm and increase knowledge by considering sexual homicides as a complex heterogenous crime.

Lethal combinations: A conjunctive analysis of crime scene behavior associated with sexual homicide

This research investigates violent stranger rapes and the factors leading these cases to sexual homicides. Variables relating to modus operandi characteristics on one part and offender behavior on the other part are examined using conjunctive analysis of cases configuration to identify the different combinations leading to a lethal outcome. Using a French sample of 1263 cases of violent rapes and 303 cases of sexual homicides involving female adult victims, we find that blows given by offenders and information about physical resistance of victims are strongly associated intentional and non-intentional sexual homicides. Psychoactive substance consumption by offenders as well associal isolation are in a lesser extend also associated with the lethal outcome.

The Sexual Murderer Is a Distinct Type of Offender

The current study investigates the question of the specificity of sexual homicide offenders by comparing three types of crimes: sexual homicide, nonsexual homicide, and violent sexual assault. The comparison is based on victim, offender and modus operandi characteristics throughout 102 variables. The sample has been taken from a French national police database including 1,736 cases. Among these cases, there are 463 nonsexual homicides, 173 sexual homicides and 1,100 violent sexual assaults. Bivariate and multivariate analyses are performed to highlight the differences. Major differences are observed between, on one hand, sexual homicides and, on the other hand, nonsexual homicides and violent sexual assaults. These differences focus mainly on the offender and modus operandi characteristics. By analyzing specifically the type of observed differences, this research suggests that the sexual murderer and his crime should be analyzed through the lens of a unique type of crime. Findings present implications in terms of correctional practices, offender treatment, and rehabilitation.

Sexual Homicides in China: Exploring the Offender, Victim, and Offense Characteristics

Nearly all information available on sexual homicides are limited to studies conducted in the West. Little is known about sexual homicides that occurred in China. The current study is arguably the first to explore the offender, victim, and offense characteristics of Chinese sexual homicides. Over a period of 23 years (1994 to 2016), the data of 59 cases collected from two data sources (i.e., published Chinese case reports and police data) are examined. Findings indicate that heterosexual assaults are far more prevalent in Chinese sexual homicides. Sexual murderers who averagely aged 32.44 years are mostly males (97%), single (67%), secondary school educated (68%), and with no prior overall (80%) and sexual (88%) convictions. The victims are mostly females (83%) with mean age of 35.35 years. The frequently observed offending patterns include strangers as victim choice (63%), con tactics as victim approach method (57%), sexual pleasure as primary motivation (49%), and personal weapons as murder weapon of choice (41%). Vaginal penetration is a commonly observed sexual assault (88%) and victim body mutilation is also not uncommon (47%). Three case examples are also presented to illustrate the diverse nature and offending patterns of Chinese sexual homicide offenders.

The Unusual Suspects: Multiple-Perpetrator and Multiple Concurrent Victim Sexual Homicide

Sexual homicide typically implies a crime involving two people: perpetrator and victim. Thus, multiple-perpetrator and multiple concurrent victim sexual murderers are unusual, empirically invisible due to their exclusion from (or burying within) research samples. The present study examines 21 such cases of male sexual murderers having perpetrated at least one sexual homicide either together with a co-offender or alone but killing two victims at once. The aim was to investigate just how unusual, or not, these cases may be in relation to current scientific understanding of sexual murderers and their crimes. A descriptive analysis of offenses (co-offender and offender-victim dynamics, modus operandi) and offender characteristics is presented. Main findings, that multiple-perpetrator and multiple concurrent victim sexual murderers are not so unusual in that they are well conceptualized through application of the established sexualized, grievance, and rape murderer typology, are discussed in relation to clinical and empirical implications.

Sexual Sadism and Psychopathy in Sexual Homicide Offenders: An Exploration of Their Associates in a Clinical Sample

Sexual sadism and psychopathy are often considered synonymous with sexual homicide, but there is limited research on their associates in sexual homicide offenders. Associates of dimensional measures of sexual sadism (Sexual Sadism Scale; SeSaS) and psychopathy (Psychopathy Check List-Revised [PCL-R] total, Factor 1, and Factor 2) were examined in 51 male Scottish cases. Over a third were DSM-IV (Diagnostic and Statistical Manual of Mental Disorders-IV) sexual sadists, just under a third screened in with the SeSaS, and a quarter were "Hare psychopaths." Sexual sadism and PCL-R measures were moderately associated. Sexual sadism predicted control, sexual deviance, and unusual behaviour at crime scenes; attempted homicide and having a co-accused; and multiple sexual homicides and previous sexual offending. PCL-R Factor 1 predicted violent, exploitative, and evading detection behaviours at crime scenes; completed homicide; and previous violent offending. PCL-R Factor 2 predicted impulsive behaviours at crime scenes, substance misuse, and previous general offending. Psychopathy and sexual sadism play key roles in sexual homicide, interact with each other, and determine different aspects of offences and offenders.

Male and Female Single-Victim Sexual Homicide Offenders: Distinguishing the Types of Weapons Used in Killing Their Victims

Most studies have focused on male sexual homicide offenders (SHOs) without testing whether sex differences exist. Accordingly, little is known about the distinctions between male and female SHOs, particularly with respect to their use of weapons in killing their victims. This study used a sample of 3,160 single-victim sexual homicide cases (3,009 male and 151 female offenders) from the U.S. Supplementary Homicide Reports database to explore sex differences in the types of murder weapons used by offenders in killing victims over the 37-year period 1976 to 2012. Findings indicated that significantly more male SHOs used personal weapons (43%) and more female SHOs used firearms (63%) in their offense commission. In general, female offenders predominantly used weapons that were physically less demanding (e.g., firearms and edged and other weapons; 89%). Different trends in the murder weapons used by male and female SHOs from different age groups were observed. Interestingly, findings showed that the type of weapon used by SHOs was in part influenced by the victims and their characteristics.