's Trail of Terror From the Beginning of Taking Life Until The End of His Life Serial killers tend to be white heterosexual males in their twenties and thirties. While it is impossible to predict who will become a serial killer there are traits that appear to be similar in all killers. These behaviors include cruelty to animals, bedwetting, lying, drug and alcohol abuse, and a history of violence. According to Robert Ressler et al., "serial homicide involves the murder of separate of separate victims with time breaks between victims, as minima ....