Criminologist Eric Hickey’s database research on the demographics of serial killing highlights that 88% are male and 85% Caucasian and average age of 28.5 (E, Hickey. 2006). In terms of victim selection, Hickey’s empirical research further demonstrates that 62% target strangers exclusively and another 22% kill at least one stranger (E, Hickey. 2006). Additionally, 71% of the killers operated in a specifically targeted location or area, rather operating in multiple locations.
Moreover, Wilson further refers to the “cooling off period” and patterns of similarity in the method of killing (D, Wilson. 2001). Reference is made to serial killer Wayne Gacy who would gag victims with their own underwear in order that they would die in their own vomit (J. Silverman, D. Wilson, 2002).
Notwithstanding criminological observations regarding parallel trends in serial killer behaviour, scientific findings regarding physiological causal factors remain inconclusive to describe the motivations behind the actions of a serial killer (Vronsky 2004). Indeed, the attempts of social science, biological and criminological theory to explain differences between male and female violence in context of serial killers further highlights the flawed attempt to propound a conclusive and all encompassing rationale to explain the actions of serial killers (Vronsky 2004).