Serial killers hold our fascination, whether in the news media, television shows such as Criminal Minds, or popular movies such as the Hannibal Lecter. Serial killers seem so purely predatory that our culture today cannot help but feel a macabre interest in them.


Serial killers differ from mass murderers or spree murderers. A mass murder can be defined as the killing of multiple people at a single location; victims may be random or targeted. A spree murder is the killing of multiple people at different locations over a short period of time (the maximum is usually 7 days). The killer in spree murders usually knows his victims and most often targets family members or romantic partners.

The common definition for serial killers was created by the FBI, which defines a serial killer by three criteria:

  1. The individual must kill in three or more separate events.
  2. All three murders must take place in separate locations.
  3. The killer must have an emotional cooling off period between murders.

The key distinction between serial killers and mass or spree killers is this cooling off period.

There is some disagreement over this definition, mostly about the number of killings required. There is also debate as to whether hit-men should be considered serial killers.

Profile of a Serial Killer

The average serial killer usually exhibits the following traits:

  • Intelligent
  • Charismatic
  • History of a troubled childhood and/or a broken family
  • History of violence against others and against animals
  • Fixation on fire at a young age
  • History of bedwetting
  • Unable to hold on to long-term relationships (however, the killer may have been/be married, or have children, but they are emotionally distant from their family)
  • May have a physical deformity
  • May have a head injury
  • White
  • Male
  • Around 25-35 years of age
  • Interest in pornography, specifically violent pornography
  • Psychopathy

The criminal profile of a serial killer can be better established once it has been determined whether the killer is organized or disorganized.


Organized serial killers are planners: they plan everything from the abduction, the murder itself, and the escape from the scene. These killers often have a certain ‘type’ which they victimize, and often stalk their victim ahead of time while they formulate a plan. These killers are often intelligent, methodological and orderly, socially competent, and employed. Organized killers are more likely than disorganized killers to be married and have children. They are charming, and will often use their charm to deceive their victims. These killers will have a vehicle and bring their own weapons to the murder scene. If the killer takes a trophy it will generally not be a body part as they decompose and smell. Their crime scenes contain signature elements; they act out a fantasy and are perfectionists. Organized killers follow themselves in the media and the longer they continue to kill, the harder they are to catch.


Disorganized serial killers are unpredictable and act without a strict plan, which can make them just as difficult to catch as organized killers. These killers attack based on opportunity, usually close to where they live (usually have no vehicle). They too have murderous fantasies, but their fantasies are very vague and incomplete compared to those of an organized killer. Disorganized killers are often socially inept and are either unemployed or have a low skilled job. They make no effort to hide what they have done, and do not attempt to to clean up the crime scene. They use weapons found at the scene and often ‘overkill’, leaving the bodies of their victims mutilated. If a disorganized killer takes a souvenir, it is most likely a body part.


There are four common typologies of serial killers:

  1. Visionary Killer: This killer feels compelled to kill because of ‘voices’ in their heads or visions that tell them to do so. For example, Herbert Williams Mullin claimed to hear voices that told him a disastrous earthquake was imminent, but he could save California through murder. Mullin killed thirteen people in an effort to ‘save California’. It was later determined that Mullin suffered from paranoid schizophrenia.
  2. Mission Oriented Killer: These individuals feel that it is their duty or mission to kill certain kinds of people. For example, Ted Kaczynski, commonly referred to as the Unabomber, started a bombing campaign in an effort to save the environment, which he felt was being destroyed around him. He targeted places that were creating ‘high technology’ such as universities and airlines. Kaczynski’s bombs killed three people and injured twenty-three.
  3. Power-Control Killers: These killers seek complete control over their victims. Sexual activity is almost always involved in these cases. John Wayne Gacy,“The Clown Killer”, would fall into this category. Gacy murdered and raped 33 teenage boys, burying 26 of them in the crawl space of his home.
  4. Hedonistic Serial Killers: This is the most common type of serial killer. These individuals kill for the thrill and enjoyment they get from the act of killing. There are three subtypes of hedonistic killers:
    1. Hedonistic comfort killers: Killing victims provides the killer with some sort of comfort; usually money. Dorthea Puente ran a boarding house in California where she killed her elderly tenants and buried them in the backyard so she could claim their social insurance checks.
    2. Hedonistic lust killers: The serial sexual predator; fantasy plays a large role and their satisfaction depends on the amount of torture and mutilation they inflict on their victims. Jeffrey Dahmer is one of the best-known hedonistic lust killers. He searched for a beautiful, submissive, and eternal lover. Dahmer killed 17 men and boys in this search for his perfect lover; his murders involved rape, torture, dismemberment, necrophilia, and cannibalism (so that a part of his victims would stay with him forever).
    3. Hedonistic thrill killers: Their primary thrill is to create fear and death. The act is usually not sexual and is not drawn out over period of time, they are solely interested in the kill. Hedonistic thrill killers often work in teams. The notorious “Zodiac Killer” claimed to be responsible for 37 murders but investigators have only been able to pinpoint 7 victims, two of which survived. The Zodiac killer sent taunting letters to the police, and was never caught or identified.

Female Serial Killers

Although males make up the majority of serial killers, there are female serial killers as well and they differ from men in many ways. Research shows that the majority of males (50%) kill for sexual pleasure while females kill for profit (75%), control (13%), or revenge (12%). Men tend to be more actively violent in their killing, raping, torturing, beating or strangling their victims while females are usually passive and tend to favour poison. The victimologies differ as well; men tend to chose strangers while women target relatives, friends, and romantic partners. One of the most surprising differences is the length of time over which each gender continues killing. Men usually kill for a short period, a few months to about 4 years. Women, on the other hand, kill for an average of 6-8 years, sometimes even decades.

There are six typologies that female serial killers fall into:

  1. Black Widow: Most of their victims are relatives, romantic relationships, or close friends. Black widows kill for monetary gain, most often life insurance. These women often kill 6-8 people over a period of ten to fifteen years and their preferred method is poison.Example: Lydia Trueblood killed five husbands, her brother in-law, and her baby daughter.
  2. Angel of Death: These women are workers in hospitals or senior homes where death is not uncommon. They are exhilarated by their power over life and death and often bring their patients to the brink of death before miraculously curing them, though most victims are eventually killed. These women often suffer from Munchausen’s by proxy syndrome or a God complex. This type of killer usually claims 8-12 victims over a 1-2 year period. They kill slowly with drugs or poison that mirror the effects of disease and sickness.Example: Genene Jones killed between 11 and 46 terminally ill infants by injecting them with digoxin and pretending to try to save them. Jones continued to kill even while under investigation.
  3. Sexual Predator: The rarest of female serial killers; only one known North American case. These women are usually in their 30’s and geographically mobile. They are driven by sexual fantasies of killing and kill on average 6 people in a 3 year period.Example: Aileen Carol Wuornos worked as a prostitute and killed 7 male clients. She would claim that they tried to rape her and would shoot or stab them during sex.
  4. Revenge Killer: Also rare, and generally only found among repeat offenders. These women kill family members or friends that they believe offended them. Revenge killers usually kill 3-4 victims over a two year period and tend to show remorse after the act.Example: Martha Wise killed family members and a pastor and also burnt down a church because she viewed them as barriers that kept her from marrying the man she loved. She later claimed that the devil made her do it.
  5. Team Killers: These women often do not kill on their own but are coerced into doing so by a partner. Teams are most often male-female, however the partner may also be a sister or close female friend. 35% of female serial killers fall into this category. Killings are often sexual in nature and there are usually 9-15 victims in a two-year period.Example: Charlene and Gerald Gallego raped, tortured and buried alive over 20 girls. Charlene helped Gerald because he claimed that taking virgins would cure his impotency.
  6. Profit Killers: Essentially hit women, these women tend to be the most intelligent of the female serial killers are very dispassionate.Example: Madame Popova was a Russian hit woman that hired herself out to women who had cruel and abusive husbands. She killed more than 300 men.


In general, we have a poor understanding of the reasons some people turn out to be serial killers. Research has at least found some reoccurring themes and generated a number of theories. There seems to be no single thing that causes a person to become a serial killer, but rather an interaction of different risk factors.

Anomie Theory

The first and oldest theory is the anomie theory, which posits that serial killers lack any bonds tying them to society. It is believed that family history and childhood development play large roles in this. With this separation from society, many serial killers believe that they should be able to do what they want, when they want (ethos of personal satisfaction). Many serial killers were adopted, or have never met one parent. Neglect (especially from mothers) and abuse are common themes in serial killers’ childhoods. This may cause feelings of inadequacy, worthlessness, and powerlessness, which may lead to extreme sexual dysfunction. Feelings of sexual inadequacy and a rich fantasy life are common cognitive factors that influence and encourage serial killers to kill, rape, and torture their victims. It is only through these methods that the killer can be sexually satisfied.

Biological Theories

Some research points to brain anomolies in serial killers; possibly due to abnormal development during gestation or the result of an injury. A large number of serial killers studied showed severe damage to the frontal lobe. There is also some evidence that abnormalities in the nervous system may play a role. The ANS (autonomic nervous system), which acts as the body’s ‘control system’, is responsible for sexual arousal. It has been hypothesized that damage to this area may result in the serial killer’s twisted sexual fantasies.

The Diathesis-Stress Model (Giannangelo 1996)

This model proposes that all potential serial killers have a cognitive susceptibility to both behave and think in ways that, if combined with environmental stressors and traumas, can lead to serial killing.

Biological predisposition   →   self-esteem and self control problems   →   maladaptive coping skills;   →   retreat into fantasy world   →   dissociative process   →   first kill (usually an accident.)

Other Factors

There has been a dramatic increase in the number of serial killers in the past 60+ years. Although some of this rise is the result of increased identification of serial killers by police, changes in society have actually increased the number of serial killers. Factors such as increased urbanization, technology, and the availability of personal vehicles has, in a sense, made serial killing easier than it was in the past.

Police Response

Serial killers are the most difficult offenders to apprehend. They are often very intelligent, some are even geniuses, and their meticulous planning allows them to kill numerous victims before being caught – if they are ever caught at all. Although there is often a pattern in the victimology, investigators may only recognize and understand it after the case is solved.

To better understand and study serial killers, the ISU (investigative support unit) of the FBI has developed methods of profiling serial killers. The ISU conducted in-depth interviews and formal psychological testing on incarcerated killers to come up with a basic list of traits. Members of the RCMP Behavioural Sciences unit have trained in Quantico Virginia with the FBI to develop profiling methods to be employed in Canadian cases. These profiles, however, are based on serial killers who have been apprehended.

Another barrier in serial killer investigations is that killers will often abduct and kill individuals across different jurisdictions. Sometimes police in two different communities are both searching for a killer, without realizing that they are looking for the same one; this is called linkage blindness. To help prevent linkage blindness, the FBI has created VICAP, the Violence Criminal Apprehension Program, which collects information on unsolved cases from all jurisdictions. With this program, law enforcement can link a number of homicides committed in different communities to a single offender. After the Clifford Olsen case, Canadian police forces developed a similar program and created ViCLAS, the Violent Crime Linkage System.

Canadian Serial Killers

Clifford Olson

Olson had been in trouble with the law from a very young age. As a child he was known as a bully who was rumoured to have tortured and killed animals. Before he began to kill he spent time in jail for robbery and fraud. In 1980, Olson killed 11 young men and women between the ages of 9 and 18. He travelled across British Columbia to find his victims and was finally caught in 1981 while attempting to abduct two young girls. Olson made a deal with the police to release the whereabouts of the bodies if his wife received $100,000 ($10 000 per body, as Olson deemed the first to be a ‘freebie’). Police made the deal to give closure to the families and in 1982 Olson was sentenced to 11 concurrent life sentences.

Robert Pickton

Pickton is, to date, Canada’s worst serial killer. A pig farmer from British Columbia, Pickton kidnapped and murdered prostitutes, allegedly feeding the remains to his pigs and possibly even his dinner guests. Pickton’s farm was being searched by the RCMP for illegal firearms when an officer discovered human remains. Pickton is still in front of courts and so far has been charged with the murder of 26 women. However, Pickton told an officer that his count was ‘one away from 50’.

Paul Bernardo and Karla Homolka

These cases were often referred to as the “Ken and Barbie” murderers. While dating, Bernardo and Homolka drugged and raped 15 year old Tammy Holmoka, Karla’s younger sister. The couple videotaped the night; Tammy choked to death on her own vomit. Their second victim was 14 year old Leslie Mahaffy, who they kidnapped on her way home from school in June 1991. Mahaffy was raped and beaten for over 24 hours until Bernado strangled her with an electrical cord. They body was cut into pieces, encased in cement, and thrown into a lake. The cement quickly broke apart and the body was discovered. The same day that Mahaffy’s body was discovered, Bernardo and Holmoka got married. The third victim was 15-year old Kristen French who, like Mahaffy, was raped, tortured, and strangled with the same electrical cord. French’s body was left in an illegal garbage dump.

Bernardo and Holmoka were caught in late 1992. Bernardo, who is also believed to be the Scarborough Rapist, was sentenced to life in the Kinston Penitentiary. Holmoka made a plea bargain, was convicted of manslaughter, and spent only twelve years in prison.

Other Canadian Serial Killers include:

  • John Martin Crawford
  • Miachel Wayne McGray
  • William Patrick Fyfe
  • Alan Legere
  • Nelson Earle Leonard
  • Dr. Thomas Neil Cream
  • Wayne Clifford Boden
  • Russel Maurice Johnson
  • Peter Woodcock

Public Fascination

Serial killers draw our attention. Many people find them fascinating as sideshows; they want to know what makes them ‘tick’ and what is wrong with them. The facination with serial killers, however, is deep rooted in our culture. Somehow, we have turned these monsters into a twisted type of celebrity. Their stories are published as books or made into movies. Their personal belongings, known as ‘murderabilia’, are auctioned off to the highest bidder. Serial killers can be found emblazoned on magazines, t-shirts, posters, and even trading cards. John Wayne Gacy had his own 1-900 telephone number where callers could listen to him ramble, Clifford Olson will sign his trading cards for a $10 fee, and Kenneth Bianci (Hillside Strangler) is just one of many serial killers who has received love letters and marriage proposals. Riachard Ramirez (Nightstalker) actually married a woman who sent him 75 letters. In acknowledgment of the victims’ families, there have been bans, mostly in the United States, of certain serial killer related products. Many point out that fame and notoriety is of huge importance to some serial killers. They do not deserve to gain any more satisfaction from the crimes they have committed.


There is much that we do not understand about serial killers, but what we do know is helping to identify and apprehend them. Common personality traits and typologies help to better profile active killers, allowing authorities to track them sooner and, in turn, save lives. One thing we do know is that there is no way of rehabilitating a true serial killer. Given the chance, all would kill again, and many are not afraid to openly admit it.

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Leung, Julietta. “The Personality Profile of a Serial Killer.”

RCMP. “Violent Crime Linkage System.”

Serial Killers. “Clifford Robert Olsen Jr” 2008.

Serial Killers. “Paul Kenneth Bernardo and Karla Homolka.” 2008.

Serial Killers. “Robert William Pickton.” 2008.

Wikipedia. “Dorthea Puente.” November 1, 2010.

Wikipedia. “Herbert Mullin.” October 3, 2010.

Wikipedia. “Jeffrey Dahmer.”