Serial killer
A serial killer is defined as an individual who commits two or more murders in separate incidents, often driven by motives such as anger, thrill, sexual perversion, financial gain, or a desire for attention. This behavior is distinct from mass murderers, who kill multiple people in a single event. Throughout history, notable figures such as Vlad the Impaler and Elizabeth Bathory have gained infamy for their violent acts, while more modern examples include notorious killers like Ted Bundy and Aileen Wuornos. The motives of serial killers can vary widely, with common themes involving power, revenge, and control, and victims are often selected based on specific characteristics.
Research indicates that serial killers can be both male and female, though the majority are male, leading to a disparity in media focus. Female serial killers, while less common, often employ methods such as poisoning. The psychology behind serial killing has been a subject of extensive study, with theories exploring the potential influence of genetics, childhood trauma, and social factors. The complex nature of serial killing continues to intrigue law enforcement and mental health professionals, as they strive to understand and prevent such violent behaviors.
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Full Article
The Federal Bureau of Investigation (FBI) defines a serial killer as a person who commits two or more murders in separate events, motivated by anger, thrill, sexual perversion, financial gain, or attention. This is in contrast to mass murderers, who kill numerous people in one incident. Serial killers have been around since the dawn of humankind, but two of the earliest and most renowned serial killers were Prince Vlad III of Romania, who was also known as Vlad the Impaler and who became the inspiration for Bram Stoker’s Count Dracula, and Countess Elizabeth Bathory of the seventeenth-century Kingdom of Hungary, who killed hundreds of virgins and bathed in their blood. Modern serial killers often use technology to murder and dispose of their victims, and law enforcement professionals use the same technology to profile and capture them. Psychiatrists use ongoing research studies to probe the psyches of serial killers to attempt to discover why they kill and to stop them before they kill again.
Brief History
Besides the legendary exploits of Vlad III the Impaler and Countess Bathory, Thug Behram of the Thuggee cult in India established a serial killer record and contributed the word "thug" to the English language. He claimed to have been present at the deaths of more than 900 people between 1790 and 1840 and to have killed about 125 himself before his execution by hanging in 1840.
Jack the Ripper, an anonymous serial killer active from April 3, 1888, to February 13, 1891, in London's Whitechapel area, earned the title of the first serial killer of the modern era, murdering eleven women before the killings stopped abruptly.
Ed Gein, the first major twentieth-century serial killer, inspired numerous movies and books, including Psycho, The Texas Chainsaw Massacre, and The Silence of the Lambs. Police in Gein's hometown of Plainfield, Wisconsin, discovered that he exhumed bodies from local graveyards and fashioned trophies from their bones and skin. He confessed to killing only two women, but authorities suspect that he killed many more.
DNA analysis linked serial killer Ted Bundy and Gary Leon Ridgway to their victims. Other infamous twentieth-century serial killers include Charles Manson, John Wayne Gacy, Jr., Jeffrey Dahmer, and Henry Lee Lucas. Famous twenty-first century serial killers with victims in the double digits include Brazilian Pedro Rodrigues Filho and Russian Alexander Pichushkin.
Female serial killers are not as well studied and understood or as common as their male counterparts, but they have tabulated their own lists of victims. Dorothea Helen Puente, who ran a boarding house in Sacramento, California, killed and buried her older borders and those with mental disabilities in her backyard. After committing a series of petty crimes in the 1990s, Aileen Wuornos went on a killing spree, robbing and shooting at least seven men, and then claimed self-defense when she got caught. In 2002, the state of Florida executed Wuornos by lethal injection.
Overview
The motives of serial killers, including power, revenge, lust, and control, are rooted in human nature. Some serial killers choose their victims by occupation, race, appearance, gender, or age group, and some murder their victims in similar ways while others use various methods. Serial killers can be male or female. The media focuses more on male serial killers because they are more common, their crimes are usually more horrific than those of female serial killers, their victim count is higher, and they often seek attention for their crimes by leaving clues for law enforcement and to tantalize the media.
In the Encyclopedia of Serial Killers, Michael Newton states that women comprise only 8 percent of serial killers, and approximately 80 percent of them use methods like poisoning to keep themselves and their victims away from the public eye. The others resort to more gruesome methods like bludgeoning, suffocation, and stabbing.
In their 1998 study Murder Most Rare, Michael and C. Kelleher categorize male serial killers as visionary, mission focused, hedonistic, and power or control killers. They divide female killers into black widows, angels of death, sexual predators, revenge, and profit killers. They emphasize that the motives of individual serial killers may overlap categories, and that both male and female serial killers sometimes work as part of a team.
Scientists, criminologists, and academics have studied the psychology of serial killers, with some studies concluding that serial killers are born with abnormal brain activity that causes their violent behavior. The fractured identity syndrome (FID) theory derived from the work of sociologists Charles Cooley and Erving Goffman suggests that traumatic events during childhood or adolescence fracture the personality of a serial killer and result in murderous behavior. The social process theory states that serial killers murder because of peer pressure and lack of family structure, identity, and friends.
In a 1963 paper titled “The Threat to Kill,” published in the American Journal of Psychiatry, forensic psychiatrist J. M. Macdonald proposed a set of three behavioral characteristics that together may predict violent tendencies. These characteristics are called the Macdonald triad, or triad of sociopathy, and they link animal cruelty, obsession with setting fires, and persistent bedwetting past age five to violent and homicidal behavior. Although some serial killers, including Gary Ridgway and Dennis Rader, were cruel to animals in their childhood, other studies have not discovered statistically significant links between the Macdonald triad and serial killers. Many sociologists and psychiatrists came to discount the theory.
When Israel Keyes was arrested in Alaska for the murder of Samantha Koenig in 2012, he admitted to at least seven other murders and told FBI investigators that he studied the patterns and methods of other famous serial killers to develop his own style of killing and to avoid being accused of "copy cat" killings. Over the course of more than a decade, Keyes traveled the United States, picking his victims randomly. He killed himself in his jail cell in December 2012.
In England in 2000, Dr. Harold Shipman was convicted of killing up to 250 of his patients, most of whom were older women in good health. A clear motive was never established before Dr. Shipman killed himself in his jail cell in January 2004, but investigators believe Shipman enjoyed having literal control over life and death. In 2013, Brazilian doctor Virginia Helena Soares de Souza was arrested and accused of killing up to three hundred of her hospitalized patients by first administering muscle relaxants then cutting off their supply of oxygen. Her motives were to make more room in the hospital and to speed the process of death in patients who were critically ill.
Regardless of established or hypothesized motives, as serial killings continued to occur throughout the world at varying rates, experts made further attempts to explain the potential factors behind such criminal behavior. In 2025, the book Murderland: Crime and Bloodlust in the Time of Serial Killers, by Caroline Fraser, drew attention for its focus on the "lead-crime theory" that some had proposed to explain a spike in crime in the United States in the twentieth century. Rooted in hypotheses about a connection between the environment and behavior, Fraser investigates whether toxic chemicals released through industrial processes could have played a part in a proliferation of serial killers from the Pacific Northwest.
Bibliography
Angrilli, Alessandro, Giuseppe Sartori, and Giovanna Donzella. “Cognitive, Emotional and Social Markers of Serial Murdering.” Clinical Neuropsychologist, vol. 27, no. 3, 2013, pp. 485–94.
Egger, Steven. The Need to Kill: Inside the World of the Serial Killer. Prentice Hall, 2003.
Elassar, Alaa. "What Causes Someone to Become a Serial Killer? It's a Malignant Combination of Factors, Experts Say." CNN, 24 July 2023, www.cnn.com/2023/07/24/us/serial-killers-psychology/index.html. Accessed 19 Aug. 2025.
Fox, James Alan, et al. Extreme Killing: Understanding Serial and Mass Murder. 5th ed., Sage, 2024.
Holmes, Ronald M., and Stephen T. Holmes. Serial Murder. Sage, 2009.
Kelleher, Michael, and C. Kelleher. Murder Most Rare. Dell, 1998.
Keppel, Robert D., and William J. Birnes. The Psychology of Serial Killer Investigations: The Grisly Business Unit. Academic, 2003.
Macdonald, John M. “The Threat to Kill.” American Journal of Psychiatry, vol. 120, 1963, pp. 125–30.
Newton, Michael. The Encyclopedia of Serial Killers. Checkmark, 2006.
Schlesinger, Louis. "Speaking of Psychology: Understanding the Mind of a Serial Killer, with Louis Schlesinger, PhD." Interview by Kim I. Mills. Speaking of Psychology, Episode 281, American Psychological Association, www.apa.org/news/podcasts/speaking-of-psychology/serial-killer-mind. Accessed 19 Aug. 2025.
Skrapec, Candice, and Kori Ryan. “The Macdonald Triad: Persistence of an Urban Legend.” Paper presented at the American Society of Criminology Annual Meeting, San Francisco Marriott Marquis, San Francisco, California, Nov. 19, 2010.
Sweet, Jacob. "Why Was Pacific Northwest Home to So Many Serial Killers?" The Harvard Gazette, 19 Aug. 2025, news.harvard.edu/gazette/story/2025/08/why-was-pacific-northwest-home-to-so-many-serial-killers/. Accessed 19 Aug. 2025.
Vronsky, Peter. Serial Killers: The Method and Madness of Monsters. Berkley, 2004.
Wilson, Colin, and Donald Seaman. The Serial Killers: A Study in the Psychology of Violence. Virgin, 2007.