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.