Serial Killer Definition: History, Characteristics and Motives

A serial killer is a person who methodically murders a substantial number of people over a period of time. The definition of serial murder varies. The lowest number of victims is three in most cases, although certain investigative agencies move the barometer higher or lower. Law enforcement has brought many of these killers to justice over the years, but plenty of unsolved cases remain.

When most people refer to the crime sprees of serial killers, they’re thinking of a particularly notorious set of murderers from recent history. Serial killers have existed throughout all of history, however, in one iteration or another and are not unique to a particular country. Jack the Ripper, an unknown person (or persons) authorities associate with a series of slayings in Victorian England, is practically synonymous with the term “serial killer.” Henri Landru (the Bluebeard of Gambais) was a French killer from around the same era.

Serial killers often share some common traits. Here are just a few to consider:

• Childhood troubles: Some of the most prolific serial killers have long histories of brutal child abuse in their pasts. For example, Ottis Toole—convicted of six counts of murder—grew up a victim of incest and violence at the hands of relatives. This is a common element in the backstories of several serial killers. Persistent bedwetting, fire starting, and cruelty to animals during youth can also be harbingers of future serial killing.
• Lack of empathy: Serial killers almost always have a total lack of empathy, remorse, or guilt. They see themselves as entitled to torturing and killing their victims, often dehumanizing them in their eventual confessions to law enforcement.
• Manipulative personalities: Some serial killers are quite charismatic and manipulative. Ted Bundy wrapped the media around his finger during his trial. H.H. Holmes made a name for himself as a prolific swindler and con man alongside killing dozens of people. Harold Shipman was a well-respected doctor and pillar of his community who killed well over two hundred patients.
• Methodical killing style: Most serial killers murder their victims in a methodical, pattern-based fashion. For instance, Moses Sithole of South Africa chose women victims in their twenties who were unemployed. After offering them jobs, he would lead them to one of the remote areas where he committed his crimes.

While each serial killer might murder for different reasons, certain motives crop up time and time again. Consider the following:

• Hunger for power: Serial killers often murder because of a desire for power. They seek to dominate their victims, not just kill them. Some theorize the worst mass murderers of history (e.g., Adolf Hitler, Joseph Stalin, Mao Zedong, etc.) might have become serial killers if their ascension to power didn’t enable them to enact their violent crime fantasies on a wider scale.
• Notoriety: Both serial murderers and spree killers (like mass shooters) often kill in the interest of attention. The Son of Sam killer (David Berkowitz) sent letters taunting New York police. The Zodiac Killer (still unknown) sent cryptic messages about his killings to Bay Area newspapers and law enforcement agencies. Albert DeSalvo, the alleged Boston Strangler, may have turned himself in for even more murders than he actually committed in the interest of greater notoriety.
• Psychosis: Many—some would argue all—serial killers are verifiable and literal psychopaths. For instance, murderers like Ed Kemper and Jeffrey Dahmer had troubled histories before they even began killing their victims.
• Revenge: Some serial murderers use their killings as an opportunity to seek revenge against the people who wronged them. For instance, a “black widow” (e.g., female serial killer), such as Aileen Wuornos, might murder innocent men or the wrongdoers themselves to feel like they are exacting revenge upon men who brutally mistreated them.
• Sadistic pleasure: Serial killers might gain a deranged sense of delight in torturing and murdering their victims. For instance, both Ted Bundy and Gary Ridgway (the Green River Killer) preyed on young women to act out their sadistic sexual fantasies before killing them.

These are just a few of the worst serial killers in history:

1. 1. Aileen Wuornos: Although Wuornos argued her killings were in self-defense, juries convicted her of six counts of first-degree murder for crimes that occurred between November 1989 and November 1990 in Florida. The state executed her in 2002.
2. 2. Albert DeSalvo: Despite the fact DeSalvo confessed to being the Boston Strangler, people dispute the credibility of his claims. Authorities associate thirteen female victims with the Boston Strangler. In 2013, experts confirmed DNA evidence linked DeSalvo to the sexual assault and murder of one of those victims.
3. 3. David Berkowitz: The media called Berkowitz the Son of Sam after he used the phrase in a letter he mailed to New York police before they identified him. He was sentenced to serve six life sentences for murdering six young women and attempting to kill others.
4. 4. Ed Kemper: Nicknamed the “Co-ed Killer,” Kemper murdered ten people, most of them female college students he picked up while they were hitchhiking.
5. 5. Gary Ridgway: Also known as the Green River Killer, Ridgway killed more than four dozen people, the bodies of whom he tended to deposit in the woods around the Green River in Washington.
6. 6. Harold Shipman: An English doctor, Shipman killed his female victims by way of lethal injections. A jury convicted him of fifteen murders, although there is evidence he was responsible for the deaths of up to 250 people.
7. 7. Henri Landru: Nicknamed the “Bluebeard of Gambais,” Landru was a Frenchman who killed at least eleven people between 1914 and 1919. After the jury found him guilty and sentenced him to death, he died by guillotine.
8. 8. H.H. Holmes: Although convicted of just one murder, Holmes confessed to more than two dozen. Prior to his imprisonment, he was a con artist, responsible for check forgeries, insurance fraud, and other crimes. The state of Pennsylvania hanged him for the killing of Benjamin Pitezel, Holmes’s former business partner.
9. 9. Jack the Ripper: Authorities associate this unknown person (or persons) with multiple murders in Victorian England. The victims were all women, and all died from violent stabbings.
10. 10. Jeffrey Dahmer: This US American serial killer, also known as the Milwaukee Cannibal, stalked the Midwest for victims. He preserved and even ate the body parts of those he killed before being apprehended by the police.
11. 11. John Wayne Gacy: Also known as the Killer Clown, Gacy—a party clown performer— almost exclusively preyed on young men. When law enforcement brought him to justice, the remains they found buried in his house made for one of the most notorious and grisly crime scenes in history.
12. 12. Ottis Toole: Juries convicted Toole of six counts of murder plus arson. He died while in prison in Florida.
13. 13. Richard Ramirez: This Los Angeles serial murderer attacked almost twenty people and killed at least thirteen. The media referred to him as the “Night Stalker” before criminologists were able to track down and identify him.
14. 14. Ted Bundy: Responsible for crimes in Washington, Oregon, Idaho, Utah, and Colorado, Bundy had at least two dozen victims but possibly as many as a hundred. He was responsible for abducting, sexually assaulting, and killing young women across the five states.
    
15. 15. Zodiac Killer: Responsible for one of the most notorious killing sprees in US American history, the still unidentified Zodiac Killer was active in and around San Francisco in the late 1960s. The media referred to the unknown male by the name “Zodiac Killer” after he used the term Zodiac in his cryptic messages to Bay Area newspapers and law enforcement agencies.

To investigate a serial killer, various levels of law enforcement will work together. If a local pattern emerges, the relevant police department might coordinate with the Federal Bureau of Investigation (FBI). If a more disparate geographical pattern of killings crops up, investigators might begin to reach out to other areas about cold cases of a similar ilk.

Investigative task forces might work for years or even decades to identify a serial killer. They seek to connect separate events over a sustained period of time, as well as to build a psychological profile of the killer. This helps narrow down the search for the perpetrator. They then tie together clues left behind to capture the murderer. Sometimes they’re successful—other times, cases stay cold and mysteries remain unsolved.

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