The motives of serial killers are generally placed into four categories: visionary, mission-oriented, hedonistic and power or control; however, the motives of any given killer may display considerable overlap among these categories.[70][71]
Visionary
Visionary serial killers suffer from psychotic breaks with reality, sometimes believing they are another person or are compelled to murder by entities such as the Devil or God.[72] The two most common subgroups are "demon mandated" and "God mandated".[73]
Herbert Mullin believed the American casualties in the Vietnam War were preventing California from experiencing the Big One. As the war wound down, Mullin claimed his father instructed him via telepathy to raise the number of "human sacrifices to nature" in order to delay a catastrophic earthquake that would plunge California into the ocean.[74] David Berkowitz ("Son of Sam") is also an example of a visionary killer. He claimed a demon transmitted orders through his neighbor's dog and instructed him to commit murder.[75]
Mission-oriented
Mission-oriented killers typically justify their acts as "ridding the world" of a certain type of person perceived as undesirable, such as homosexuals, prostitutes, or people of different ethnicity or religion; however, they are generally not psychotic.[76] For example, the Zebra killers in the San Francisco Bay Area specifically targeted Caucasians.[77] Some see themselves as attempting to change society, often to cure a societal ill.[78]
Hedonistic
This type of serial killer seeks thrills and derives pleasure from killing, seeing people as expendable means to this goal. Forensic psychologists have identified three subtypes of the hedonistic killer: "lust", "thrill" and "comfort".[79]
Lust
John Floyd Thomas, Jr. murdered at least 17 women
Sex is the primary motive of lust killers, whether or not the victims are dead, and fantasy plays a large role in their killings. Their sexual gratification depends on the amount of torture and mutilation they perform on their victims. They usually use weapons that require close contact with the victims, such as knives or hands. As lust killers continue with their murders, the time between killings decreases or the required level of stimulation increases, sometimes both.[79][80][81]
Kenneth Bianchi, one of the "Hillside Stranglers", murdered women and girls of different ages, races and appearance because his sexual urges required different types of stimulation and increasing intensity.[81] Jeffrey Dahmer searched for his perfect fantasy lover—beautiful, submissive and eternal. As his desire increased, he experimented with drugs, alcohol, and exotic sex. His increasing need for stimulation was demonstrated by the dismemberment of victims, whose heads and genitals he preserved, and by his attempts to create a "living zombie" under his control (by pouring acid into a hole drilled into the victim's skull). Dahmer once said, "Lust played a big part of it. Control and lust. Once it happened the first time, it just seemed like it had control of my life from there on in. The killing was just a means to an end. That was the least satisfactory part. I didn't enjoy doing that. That's why I tried to create living zombies with … acid and the drill." He further elaborated on this, also saying, "I wanted to see if it was possible to make—again, it sounds really gross—uh, zombies, people that would not have a will of their own, but would follow my instructions without resistance. So after that, I started using the drilling technique."[82] He experimented with cannibalism to "ensure his victims would always be a part of him".[83]
Thrill
Main article: Thrill killing
The primary motive of a thrill killer is to induce pain or terror in their victims, which provides stimulation and excitement for the killer. They seek the adrenaline rush provided by hunting and killing victims. Thrill killers murder only for the kill; usually the attack is not prolonged, and there is no sexual aspect. Usually the victims are strangers, although the killer may have followed them for a period of time. Thrill killers can abstain from killing for long periods of time and become more successful at killing as they refine their murder methods. Many attempt to commit the perfect crime and believe they will not be caught.[79][84] Robert Hansen took his victims to a secluded area, where he would let them loose and then hunt and kill them.[84] In one of his letters to San Francisco Bay Area newspapers, the Zodiac Killer wrote "[killing] gives me the most thrilling experience it is even better than getting your rocks off with a girl".[85] Coral Watts was described by a surviving victim as "excited and hyper and clappin' and just making noises like he was excited, that this was gonna be fun" during the 1982 attack.[86] Slashing, stabbing, hanging, drowning, asphyxiating, and strangling were among the ways Watts killed.[87]
Comfort (profit)
Material gain and a comfortable lifestyle are the primary motives of comfort killers. Usually, the victims are family members and close acquaintances. After a murder, a comfort killer will usually wait for a period of time before killing again to allow any suspicions by family or authorities to subside. They often use poison, most notably arsenic, to kill their victims. Female serial killers are often comfort killers, although not all comfort killers are female.[79][88][89] Dorothea Puente killed her tenants for their Social Security checks and buried them in the backyard of her home.[90] H. H. Holmes killed for insurance and business profits.[91] Professional killers ("hitmen") may also be considered serial killers.[92] Richard Kuklinski charged tens of thousands of dollars for a "hit", earning enough money to support his family in a middle-class lifestyle (Bruno, 1993).[93]
Some, like Puente and Holmes, may be involved in and/or have previous convictions for theft, fraud, non payment of debts, embezzlement and other crimes of a similar nature. Dorothea Puente was finally arrested on a parole violation, having been on parole for a previous fraud conviction.[94]
Power/control
The main objective for this type of serial killer is to gain and exert power over their victim. Such killers are sometimes abused as children, leaving them with feelings of powerlessness and inadequacy as adults. Many power- or control-motivated killers sexually abuse their victims, but they differ from hedonistic killers in that rape is not motivated by lust but as simply another form of dominating the victim.[95] Ted Bundy traveled around the United States seeking women to control.[96]
