Sexual Homicide Committed by a Family Member: Report of Two Cases and Discussion of Its Motivation Factors

Sexual homicide is a distinctive form of homicide and an extreme form of sexual violence. This phenomenon has been well addressed in psychiatric, psychological and forensic literatures. Nevertheless, sometimes it is difficult to understand the motivations behind a sexual homicide mainly when it occurs within the closed family environment. We report two cases of women’s sexual homicide committed by a family member, other than a sexual partner or an ex-partner. The sexual character was confirmed by laboratory evidences which also allowed the offender identification. In both cases, the offenders did not have any history of violence conviction and were not under substance abuse influence. In addition, psychological autopsy has not revealed any psychiatric disorder of the offenders. In this paper, we describe the findings, we discuss the characteristics of this type of murder and its motivation factors related to our socio-cultural and legislative context. Figure 1: Scratches and nail marks around nose and mouth in case 1. Open Access


Introduction
Sexual homicide includes sexual activity before, throughout or after the commission of murder. Several terms are used, like sexual murder, sex-related homicide, sexually-motivated murder or rape-homicide, etc. to refer to all homicides where a sexual element and/or a sexual motivation were evidenced, suspected or admitted [1]. Considered as the most extreme form of sexual violence, it attracts a great attention from media and scientific community [1,2]. Despite this interest, information on sexual homicide offenders is limited [1]. Several studies have addressed the question of whether sexual murderers differ from other offenders [3][4][5][6][7]. Compared to non-sexual homicide offenders, psychopaths are significantly more likely to commit sexual homicide [8]. Indeed, personality disorder, psychopathy, paraphilia, paraphiliarelated disorders and sadistic sexual fantasy may, usually, explain this terrible form of violence [9].
As most sexual homicides are committed by males, victims are usually female stranger or casual acquaintance of the perpetrator, rather than a sexual partner or ex-partner [3]. When, other family members, free from any psychiatric disorder, are involved in this type of crime, certain factors should motivate the conversion of violent sexual acts to homicide. In this paper, we report two cases of sexual homicide committed by family members, compiled in the forensic department of Habib Bourguiba University Hospital in Sfax, Tunisia. We discuss the characteristics of this type of murder and its motivation factors related to our legislation and our sociocultural context.

Case 1
A 48 year old married woman was found dead unclothed in his bed. She has a chronic renal failure antecedent. She was living with her sister's husband's family. Her husband was in chronic coma. Despite hypothesis of natural sudden death raised by the family, a forensic autopsy was requested and performed 24 h later. The external examination has revealed asphyxia with traumatic injuries in the face, including scratches and nail marks around the nose and mouth (Figure 1). In addition, a bruise on the internal face of the upper lip is found ( Figure 2). The autopsy did not reveal any other anomalies except polycystic kidneys in relation to her chronic pathology. Toxicological analysis performed on blood, urine and gastric contents samples were negative. So, death was the result of mechanical asphyxia by oro-facial suffocation (smothering).
Samples of vaginal and anal swabs were performed within 24 h after death. Cytology analysis confirmed the presence of spermatozoa in only the vaginal cavity. The genetic study has identified a DNA profile that has subsequently confirmed the identity of the suspect. He was the sister's husband. He was, 50 year old, free of any psychiatric disorder and he had no history of violence conviction. The psychological assessments are still confidential, but in conclusion experts did not reveal any psychiatric disorder and confirmed that he was totally responsible.

Case 2
A 28 year old married woman was found dead, partially buried, 400 m from her home at 7 AM. She was lost since the evening. At 1 AM, she left home, when her husband was drinking alcohol with his friend, to join her parents' home. The examination of her clothing revealed recent tears in panties ( Figure 3). The external examination revealed the presence of asphyxia with sand covering the entire body especially the face. Many traumatic injuries were found especially in the head, face, lips, neck and limbs. The genital examination revealed the presence of multiple vital injuries. The autopsy revealed the presence of bruising in the neck muscles (Figure 4), haemorrhagic infiltration behind the oesophagus ( Figure 5), displaced fracture of the mandibles' left corner and a large scalp hematoma with a localized subarachnoid haemorrhage. Toxicological analysis performed on blood, urine and gastric contents samples were negative. So, death was the result of mechanical asphyxia most likely by manual strangulation (throttling) associated with a serious head blunt trauma.

Samples of vaginal and anal swabs were performed 24 h of death.
Cytology analysis confirmed the presence of spermatozoa in only the vaginal cavity. A genetic study has identified the criminal. He was the husband's brother. He was, 45 year old, free of any psychiatric antecedents and had no history of violence conviction. Findings of psychological autopsy are still confidential, but in conclusion experts did not reveal any psychiatric disorder and confirmed that he was totally responsible.

Discussion
Sexual homicide is the intentional killing of a person during which there is sexual behaviour of the perpetrator [1][2][3]. Homicide is classified as "sex-related" when there is evidence of sexual activity observed at the crime scene or upon the body of the victim. According to the literature, at least one of the following criteria has to be met in order for a murder to be considered sexually motivated: "(1) type of, or lack of attire on the victim, (2) exposure of the sexual parts of the victim's body, (3) sexual positioning of the victim's body, (4) insertion of foreign objects into the victim's body cavities, (5) evidence of sexual intercourse (seminal fluid on, near or in the body), (6) evidence of substitute sexual activity, interest, or sadistic fantasy such as genital mutilations and finally (7) the assailant's confession" [2,3]. In our region (south of Tunisia), sexual homicide is rare. Only 5 cases are compiled in our department during six years (2009-2014), representing 1.2% of all homicide cases which is closer to the findings reported in literature. Thereby, it accounts for only 0.1% of all police recorded crimes in Germany [10], 1% of all murders reported in the United States [11,12] and about 4% of all homicides in Canada [13].
In our first case, sexual homicide was suspected regarding to the family attempt to hide the truth by referring to the victim's chronic disease and make allusion to a natural sudden death. Moreover, the presence of injuries around the nose and mouth evoked smothering, classic mechanism of asphyxia in such cases [3,14]. In the second case, the attempt to conceal the body (by burial) and subsequently to hide the crime, the presence of recent tears on the underwear and especially the presence of genital injuries have raised the hypothesis of sexual homicide. Afterwards, the sexual character, in both cases, was confirmed by biological evidences. Samples were performed, from vaginal and rectal cavities, within 24 h after death. Cyto-genetic analysis revealed the presence of spermatozoa in the vaginal cavity and determined the DNA profile of the assailant.
Generally, sexual assault is difficult to prove in either living or deceased victims. In fact, it has been reported that only 20% to 45% of sexual assault victims show evidence of physical injuries, and even fewer show evidence of ano-genital injuries [15,16]. According to Hicks, only 8% of sexual assault victims present genital injuries [17]. In other more recent studies, it was suggested that 13 to 16% of sexual assault victims present ano-genital injuries [15,18]. Consequently, biological specimens are usually required to support the occurrence of sexual    assault. The presence of spermatozoa and an elevated prostatic acid phosphatase are the two pieces of biological evidence most often used. Anyway, an understanding of laboratory evidence and its limitations is mandatory when evaluating and interpreting the results. The absence of such evidence could indicate either that sexual assault did not occur or that the evidence is no longer positive because of certain variables like post-coital interval.
The post-coital interval between semen deposition and time of sample collection is crucial in these cases. In general, as this interval increases, the proportion of samples where the spermatozoa are detected decreases [19]. In fact, spermatozoa are sensitive to the environment and begin to degenerate within hours after ejaculation. The first sign of spermatozoa degeneration is the loss of the tail, which occurs approximately after 12 to 16 h in the vagina [15]. Initially, it has been suggested that recovery of spermatozoa during the first post-coital day is only possible in 25% of cases [20]. Later, other authors found that 50% of cervico-vaginal smears will present spermatozoa after 72 h [21]. Indeed, a variety of factors may affect the persistence of spermatozoa including seasonal temperatures, meteorological conditions, body positioning and shelter/storage conditions [19,21].
Furthermore, the post-mortem semen recovery does not necessarily follow the outcome of samples performed on living subjects [19]. Concerning living victims, the maximum reported time frames for the detection of spermatozoa or its remains were: 10 days for the vaginal cavity, 3 days for the rectal cavity and less than 24 h for the oral cavity [22][23][24][25][26]. In case of homicide, the situation is more specific. As the testimony of victims is lacking, laboratory evidence becomes even more decisive. Despite, few studies have interested in the postmortem semen recovery [15,19]. Some authors suggested that time frames of spermatozoa recovery from deceased victims may be altered as compared to living victims [27]. According to Collins et al. [15], spermatozoa are found in the deceased vagina up to 5 days (intact); 7 days (intact and heads); and 2.5 months (heads only). Occasionally, intact spermatozoa can be detected for significantly longer post-mortem periods with time frames being reported up to 34 days [15,28]. In fact, this depends essentially on the environmental temperature [28,29]. Consequently, some reports have described the recovery of sperm from frozen dead bodies where intact spermatozoa could be found for longer post-mortem periods ranging from16 days to 3 months [29][30][31].
On another side, various studies have addressed the characteristics of sexual homicide victims and offenders. As our cases, victims are usually females [9,13], but sex related homicides can involve, as well as, heterosexual and homosexual relationships [8,32]. Generally, most of the victims (65-90%) are strangers or casual acquaintances, rather than a consensual sexual partner of the offenders [8]. Nevertheless, sexual homicide of a sexual partner does occur, but it is rare [32]. In our cases, the offender was a family member, free from any psychiatric disorder, and even an underlying notion of alcohol or drug abuse has not been found. According to the literature, sexual killers are mostly males and aged less than 30 years [3,33,34]. Unlike our cases, half of them are intoxicated and one out of three is under the influence of drugs [2,33]. In addition, 30 to 50% of sexual murderers have been exposed to severe and disruptive family problems, including parental alcohol abuse, sexual abuse, mental health problems and crimes [2,35,36]. Moreover, they are often suggested to have childhood and adolescent antisocial behaviour [2,3]. Indeed, some studies suggested that they have a history of violent crimes in 50% of cases among them 25% have a history of sexual crimes [34,35].
Therefore, we note that offenders, in our cases, have an atypical profile compared to the most reported cases of sexual homicides.
Historically, it was suggested that sexual murderers are a unique type of offender and are qualitatively different from other types of sexually violent offenders. Although the literature emphasizes the importance of psychiatric co-morbidity, personality disorders (antisocial, psychopathic) and sexuality problems (paraphilias, sexual sadism) among sexual murderers [35], certain contextual factors are important to understand the lethal outcome of a sexual assault. In fact, there are other reasons for death in case of sexual homicide like accidental death, excessive use of force to perform rape and the presence of a lethal weapon at the moment of sexual assault [37,38]. Hence, recent research has suggested that sexual homicide is a dynamic crime and that sexual assaults can escalate to homicide when specific situational factors are present [38].
The common characteristic in our cases is that they occur within the closed family environment. According to the literature, homicides in the family represent a relatively stable proportion (30 to 40%) of all homicides [39][40][41]. For example, in Canada, during 2003, 37% of victims were killed by a family member [39]. In our socio-cultural context, the occurrence of rape perpetrated by someone close represents a tragedy for the whole family. Its consequences are serious for victim, offender and as well for the rest of the family members. Then, the whole family will live on "shame". This may explain the reaction of the family, in the first case, which tried to cover up the assailant in order to preserve family cohesion. Furthermore, sex assaults are sometimes followed by homicide when the offender tries to hide his crime, mainly if the victim knows him [42,43]. Contrariwise, Tunisian laws punish similarly any violent sexual crime or any planned murder. In fact, according to section 201 of the Tunisian Penal Code (TPC), it is punished by death penalty whoever committed a deliberate planned homicide. Likewise, pursuant to section 227 of the TPC, rape is punished by death penalty if committed with violence, threat or use of weapon [44]. Consequently, the sexual assault offender has more interest to eliminate his victim (the only witness to his crime) than let her lives and denounces him. Hence, our legislation, attempting to reinforce the fight against sexual crimes, may give reasons for converting crime of rape to that of homicide.

Conclusion
Sexual assault is, usually, a hidden crime where the only witness is the victim. The situation is more specific in case of sexual homicide, even more while occurring within the closed family environment. The proper evaluation of such crimes requires the crime scene analysis, the study of the autopsy findings, the correct interpretation of laboratory evidences, the evaluation of the socio-cultural context and the study of the judicial record of the offender and his potential psychopathological profile.
Preventing sexual homicide is certainly not easy. In our opinion, understanding the dynamics of this type of crime and its motivation factors is crucial. Anyway, the legislation, by its repressive and sanctioning aspects should not roll away from its primary goal, fighting against crime. Until a review of Tunisian laws on sexual assault, a comprehensive and multidisciplinary approach is greatly required in order to develop specific preventive strategies.