According to the FBI’s guidelines, a serial killer is someone who has murdered at least 3 people, with a cooling off period in between kills. The killer is usually a stranger to the victims and the motivation for murder is rarely, if ever, primarily for profit. It can be a secondary motivation or a product of the murder, but not the primary motivation.
There are several types of serial killers; they are commonly categorized by if the murders they committed were organized or disorganized. Killers are also categorized by their motivations for killing: 4 motivations for killing are: visionary, mission-oriented, hedonistic and power/control killers.
Organized and disorganized or mixed killers
Killers are categorized as organized, disorganized or mixed based on 4 characteristics: victim’s characteristics, use of vehicles in the crime, type of evidence left at the crime scene and the murderer’s actions themselves.
Organized offenders usually have an average or higher than average IQ. They often work at an occupation below their abilities and know it – which can add to their frustration.
They are often socially skilled and have families, get along with others well and can be described as charming. They can use this to lure their victims by verbally conning them instead of using brute force all the time.
Organized killers have forensic knowledge – reading up on forensic science themselves, watching crime videos and learning about how police investigations work, and using that knowledge to learn how to not leave evidence behind.
Victims are followed, the crime is planned meticulously and the scene often reflects that with a lack of incriminating evidence left behind. They usually transport victims away from the crime scene and don’t leave behind the murder weapon.
Disorganized killers usually are of below average intelligence and are socially inept. They work menial jobs, are usually sexually incompetent, live alone, more likely to have been abused as a child.
They are more likely to commit an unplanned offense, looking for victims close to them or looking in places they are familiar with. The crime scenes are usually sloppy; they are likely to leave behind the body as well as the murder weapon and other evidence.
The reasons serial killers commit their crimes also puts them in different categories. The 4 categories again are visionary, mission-oriented, hedonistic and power/ control killers.
Visionary killers are the ones who claim that voices tell them to do it. They suffer from psychotic breaks from reality and believe that a higher power is commanding their actions. They might also claim that it was another person in their body, doing the killing.
These killers believe they are getting rid of society’s ills – populations of people they believe are bad for society. Common examples are prostitutes, people of different races or religions, homosexuals.
These types of killers seek thrills and derive pleasure from killing. They are further categorized into lust killers for whom sex is the primary motivation of the act – before or after the murder. The amount of torture and the acts they perform on the victims add to their satisfaction with the kills. Thrill killers get a ‘high’ from the act of killing and getting away with it. Comfort killers usually kill for money and are more likely to kill people they know or family members.
The primary motivation of power/ control killers is domination – having and exerting total control over their victims. Rape here is used as a method of exerting control and so is murder.
These are some insights and ways to categorize serial killers though actual crimes are not so clear and there might be overlaps between characteristics and motivations for killers.