Verified by 
There is a popularly held myth that serial killers are all men. This notion is simply not true, but it's understandable why many people would hold this erroneous belief. As late as 1998, a highly regarded former FBI profiler said, "There are no female serial killers." In addition, the news and entertainment media perpetuate stereotypes that serial offenders are all men, and that women do not engage in horrible acts of violence and murder.
On the contrary, female serial killers certainly do exist, but their motivations differ significantly from their male counterparts. In particular, sex is generally much farther down on the list of motivations for female serial killers. In fact, sexual or sadistic motives are extremely rare among female serial murderers. Psychopathic traits and histories of childhood abuse are often found among the very few female serial killers who have sexual or sadistic motives.
Unlike male serial killers who are frequently driven by sexual lust, female serial murderers tend to take a much more pragmatic approach to their killings. Female serial killers are much more likely than males to kill for profit or revenge, and, therefore, they are more likely to fall into the category of a hedonist comfort/gain killer than any other type.
Unlike male serial killers who usually target unknown victims, females tend to kill men who are emotionally and physically closest to them—particularly husbands or lovers—and they generally kill to improve their lifestyle. However, victims of female serial killers are not confined to male husbands or lovers. An important psychological study of 86 female serial killers in the U.S. found that their victims also included children and the elderly (1).
The news and entertainment media have popularized the female comfort/gain killer in the cultural image of the "Black Widow." The Black Widow serial killer is a woman who murders three or more husbands or lovers for financial or material gain over the course of her criminal career. The Black Widow killer was featured in the 1944 classic dark comedy film Arsenic and Old Lace starring Cary Grant. This highly popular film tells the fictional tale of two sisters who murder elderly gentlemen by serving them elderberry wine laced with arsenic.
Although they comprise less than 15 percent of all serial killers, females are very effective in their work and they typically use quieter and less messy methods to kill than their male counterparts. The methods they use for murder are more covert or low-profile, such as murder by poisoning, which was the preferred choice or modus operandi of female serial killers in the aforementioned research study. Other methods of murder that were also identified in the study of female serial killers include shooting, stabbing, suffocation, and drowning (1).
Female comfort/gain killers are frequently involved in theft, fraud, or embezzlement prior to becoming serial killers due to their interest in material things. Although most female serial killers murder for money or other profit, some do it for the attention and sympathy they receive following the death of someone they cared for. It is not uncommon for female comfort/gain killers to be employed as caretakers in nursing homes for the elderly.
Female serial killers generally operate in a specific place that they know well, such as their home, or a health care facility where they are employed. They rarely go trolling for victims out in the open as male serial killers often do, but rather find victims in their family or workplace. Dorothea Puente, the Sacramento boarding house landlady who robbed and murdered her elderly guests, was the prototypical, female hedonist comfort/gain killer.
Occasionally, a female serial killer will become involved with a male serial killer as part of a serial killing team. In such instances, the female will typically be the more submissive of the two and help to select victims in order to please her dominant male partner. The husband and wife serial killing team of Gerald and Charlene Gallego provides an example of this rare affiliation. Between 1978 and 1980, the Gallegos killed a total of 10 victims, mostly female teenagers, whom they kept as sex slaves prior to murdering them. The victims were selected primarily for the lurid sexual gratification of Gerald Gallego, who was the dominant partner in the murderous relationship.
A notable exception to the typical characteristics of female serial killers was the notorious highway prostitute Aileen Wuornos, who killed outdoors instead of at home, used a gun instead of poison, killed strangers instead of friends or family, and killed for personal gratification and vengeance. It is my belief that Aileen Wuornos rose to infamy primarily because she was atypical of female serial killers, in that she "killed like a man."
The lack of public awareness of female serial killers prior to Aileen Wuornos was due to the virtual absence of female serial killers in the news and entertainment media. Until Wuornos, the mass media almost always depicted a serial perpetrator as a deranged man, due to the erroneous and paternalistic societal notion that women could not commit such crimes. Unlike the obscure and rarely discussed Black Widow killers throughout history, Wuornos became a popular culture icon because she defied stereotypes and did not kill "demurely," as societal norms dictate that a woman should.
Interestingly, the most prolific serial killer in all of history may have been female—Hungarian Countess Elizabeth Báthory de Ecsed, who was born on August 17, 1560. Elizabeth was a countess from the renowned Báthory family in Hungary. Following her husband's death, the countess and four collaborators allegedly tortured, sexually assaulted, and killed hundreds of girls and young women. Incredibly, Elizabeth was never tried or convicted of any crimes herself. Nevertheless, to pacify the public in 1610, the countess was placed under house arrest in the Csejte Castle, where she remained bricked in a set of rooms until her death four years later in 1614.
References
1. Frei, A., Völlm, B., Graf, M. and Dittmann, V. 2006. “Female serial killing: Review and case report.” Criminal Behaviour and Mental Health, 16 (3), pp. 167-176.
