Editing Serial killer (section)

==Characteristics==
Some commonly found characteristics of serial killers include the following:
* They may exhibit varying degrees of [[mental illness]] or [[psychopathy]], which may contribute to their homicidal behavior.<ref>{{harvnb|Morton|2005}}, {{harvnb|Skeem|Polaschek|Patrick|Lilienfeld2011|pp=95–162}}</ref>
** For example, someone who is mentally ill may have [[psychotic]] breaks that cause them to believe they are another person or are compelled to murder by other entities.{{sfn|Bartol|Bartol|2004|p=145}}
** Psychopathic behavior that is consistent with traits common to some serial killers include sensation seeking, a lack of [[remorse]] or [[Guilt (emotion)|guilt]], [[impulsivity]], the need for control, and predatory behavior.<ref name="fbi.gov">{{harvnb|Morton|2005}}</ref> [[Psychopaths]] can seem 'normal' and often quite [[Superficial charm|charming]], a state of adaptation that [[psychiatrist]] [[Hervey M. Cleckley|Hervey Cleckley]] called the "[[The Mask of Sanity|mask of sanity]]".<ref>{{Cite journal |last=Cleckley |first=Hervey M. |year=1951 |title=The Mask of Sanity |url=http://www.tandfonline.com/doi/full/10.1080/00325481.1951.11694097 |journal=Postgraduate Medicine |volume=9 |issue=3 |pages=193–197 |doi=10.1080/00325481.1951.11694097 |pmid=14807904 |issn=0032-5481|url-access=subscription }}</ref>[[File:LuisGaravitoHeadshots.png|thumb|Colombian serial killer [[Luis Garavito]], also known as ''{{lang|es|La Bestia}}'' ("The Beast"). His father subjected him to severe physical and emotional abuse.]]
* They were often [[child abuse|abused]]—[[Psychological abuse|emotionally]], [[physical abuse|physically]], or [[Child sexual abuse|sexually]]—by a family member.<ref name="Tick"/>
* Serial killers may be more likely to engage in [[Sexual fetishism|fetishism]], [[partialism]] or [[necrophilia]], which are [[paraphilia]]s that involve a strong tendency to experience the object of erotic interest almost as if it were a physical representation of the symbolized body. Individuals engage in paraphilias which are organized along a continuum; participating in varying levels of fantasy perhaps by focusing on body parts (partialism), symbolic objects which serve as physical extensions of the body (fetishism), or the anatomical physicality of the human body; specifically regarding its inner parts and sexual organs (one example being necrophilia).{{sfn|Silva|Leong|Ferrari|2004|p=794}}
* A disproportionate number exhibit [[Macdonald triad]] predictors of future violent behavior:
** Many are fascinated with [[Pyromania|fire setting]].<ref name="Tick"/>
** They are involved in [[Sadomasochism|sadistic]] activity; especially in children who have not reached sexual maturity, this activity may take the form of [[zoosadism|torturing animals]].<ref name="Tick"/>
** More than 60 percent, or simply a large proportion, [[enuresis|wet their beds]] beyond the age of 12.<ref name="Tick"/>{{sfn|Singer|Hensley|2004|pp=48, 461–476}}
* They were frequently [[bullying|bullied]] or socially isolated as children.<ref name="Tick"/> For example, [[Henry Lee Lucas]] was ridiculed as a child and later cited the mass rejection by his peers as a cause for his hatred of everyone. [[Kenneth Bianchi]] was teased as a child because he urinated in his pants, suffered twitching, and as a teenager was ignored by his peers.<ref name="Tick" />
* Some were involved in petty crimes, such as fraud, theft, [[vandalism]], or similar offenses.{{sfn|Mount|2007|pp=131–133}}
* Often, they have trouble staying employed and tend to work in menial jobs. The FBI, however, states, "Serial murderers often seem normal; have families and/or a steady job."<ref name="fbi.gov" /> Other sources state they often come from unstable families.<ref name="Tick"/>
* Studies have suggested that serial killers who got caught generally have an average or low-average [[Intelligence quotient|IQ]], although they are often described, and perceived, as possessing IQs in the above-average range.<ref name="Tick">{{cite web|first=Shirley Lynn |last=Scott |title=What Makes Serial Killers Tick? |publisher=[[truTV]] |access-date=January 9, 2011 |url=http://www.trutv.com/library/crime/serial_killers/notorious/tick/victims_1.html |url-status=dead |archive-url=https://web.archive.org/web/20100728094415/http://www.trutv.com/library/crime/serial_killers/notorious/tick/victims_1.html |archive-date=July 28, 2010}}</ref><ref name="fbi.gov" /><ref name="The Root">Holloway, Lynette. [http://www.theroot.com/views/course-there-are-black-serial-killers Of Course There Are Black Serial Killers] {{webarchive|url=https://web.archive.org/web/20131013160336/https://www.theroot.com/views/course-there-are-black-serial-killers |date=October 13, 2013 }}. ''[[The Root (magazine)|The Root]]''.</ref> A sample of 202 IQs of serial killers who got caught had a median IQ of 89.<ref>{{Cite web|url=http://maamodt.asp.radford.edu/Serial%20Killer%20Information%20Center/Serial%20Killer%20IQ.htm|title=Serial Killer IQ|access-date=May 13, 2009|archive-date=March 4, 2016|archive-url=https://web.archive.org/web/20160304124633/https://maamodt.asp.radford.edu/Serial%20Killer%20Information%20Center/Serial%20Killer%20IQ.htm|url-status=live}}</ref>  Some organized serial killers who got caught have a slightly higher IQ score averaging a little bit over 99, to where disorganized killers average just under 93 in theirs. The average IQ of serial killers who got caught is 94.7.<ref>{{Cite web |title=Serial Killers: Insane or Super Intelligent?  |url=https://www.psychologytoday.com/us/blog/captivating-crimes/202006/serial-killers-insane-or-super-intelligent |access-date=2023-02-11 |website=www.psychologytoday.com |archive-date=January 7, 2024 |archive-url=https://web.archive.org/web/20240107113507/https://www.psychologytoday.com/us/blog/captivating-crimes/202006/serial-killers-insane-or-super-intelligent |url-status=live }}</ref>

There are exceptions to these criteria, however. For example, [[Harold Shipman]] was a successful professional (a [[General Practitioner]] working for the [[National Health Service|NHS]]). He was considered a pillar of the local community; he even won a professional award for a children's asthma clinic and was interviewed by [[Granada Television]]'s ''[[World in Action]]'' on [[ITV (TV channel)|ITV]].<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/uk_news/3391897.stm |title=UK &#124; Harold Shipman: The killer doctor |work=BBC News |date=January 13, 2004 |access-date=July 29, 2010 |archive-date=December 1, 2019 |archive-url=https://web.archive.org/web/20191201003208/http://news.bbc.co.uk/2/hi/uk_news/3391897.stm |url-status=live }}</ref> [[Dennis Nilsen]] was an ex-soldier turned civil servant and trade unionist who had no previous criminal record when arrested. Neither was known to have exhibited many of the tell-tale signs.<ref>{{cite web|url=http://www.trutv.com/library/crime/serial_killers/predators/nilsen/alone_4.html |title=CrimeLibrary.com/Serial Killers/Sexual Predators/Dennis Nilsen – Growing Up Alone – Crime Library on |publisher=Trutv.com |date=November 23, 1945 |access-date=July 29, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100106081640/http://www.trutv.com/library/crime/serial_killers/predators/nilsen/alone_4.html |archive-date=January 6, 2010 }}</ref> [[Vlado Taneski]], a crime reporter, was a career journalist who was caught after a series of articles he wrote gave clues that he had murdered people.<ref>{{cite news |url=https://www.independent.co.uk/news/world/europe/serial-murder-journalist-commits-suicide-852848.html |title='Serial murder' journalist commits suicide |work=The Independent |date=June 24, 2008 |access-date=July 29, 2010 |location=London |first=Konstantin |last=Testorides |archive-date=May 14, 2019 |archive-url=https://web.archive.org/web/20190514063501/https://www.independent.co.uk/news/world/europe/serial-murder-journalist-commits-suicide-852848.html |url-status=live }}</ref> [[Russell Williams (criminal)|Russell Williams]] was a successful and respected career [[Royal Canadian Air Force]] Colonel who was convicted of murdering two women, along with fetish burglaries and rapes.{{sfn|Mellor|2012}}
[[File:Ottis Toole.jpg|thumb|150px|Mug shot of serial killer, [[Human cannibalism|cannibal]] and [[necrophile]] [[Ottis Toole]]]]

===Development===
[[File:Bundesarchiv Bild 102-00824, Hannover, Prozeß gegen Friedrich Haarmann.jpg|thumb|German serial killer [[Fritz Haarmann]] with police detectives, November 1924]]

Many serial killers have faced similar problems in their childhood development.<ref name="PlotnikKouyoumdjian2010">{{cite book|author1=Rod Plotnik|author2=Haig Kouyoumdjian|title=Introduction to Psychology|url=https://books.google.com/books?id=2txsCgAAQBAJ&pg=PA509|year=2010|publisher=Cengage Learning|isbn=978-1-111-79100-1|page=509|access-date=September 1, 2020|archive-date=January 20, 2021|archive-url=https://web.archive.org/web/20210120052954/https://books.google.com/books?id=2txsCgAAQBAJ&pg=PA509|url-status=live}}</ref> Hickey's Trauma Control Model explains how early childhood trauma can set the child up for [[Deviance (sociology)|deviant behavior]] in adulthood; the child's environment (either their parents or society) is the dominant factor determining whether or not the child's behavior escalates into homicidal activity.{{sfn|Holmes|Holmes|2000|p=107}}

Family, or lack thereof, is the most prominent part of a child's development because it is what the child can identify with on a regular basis.{{sfn|Tithecott|1997|p=38}} "The serial killer is no different from any other individual who is instigated to seek approval from parents, sexual partners, or others."{{sfn|Hale|1993|p=41}} This need for approval is what influences children to attempt to develop social relationships with their family and peers. "The quality of their attachments to parents and other members of the family is critical to how these children relate to and value other members of society."{{sfn|Hasselt|1999|p=162}}

Wilson and Seaman (1990) conducted a study on incarcerated serial killers, and what they concluded was the most influential factor that contributed to their homicidal activity.{{sfn|Wilson|Seaman|1992}} Almost all of the serial killers in the study had experienced some sort of environmental problems during their childhood, such as a broken home caused by divorce, or a lack of a parental figure to discipline the child. Nearly half of the serial killers had experienced some type of physical or sexual abuse, and more of them had experienced emotional neglect.{{sfn|Hasselt|1999|p=162}}

When a parent has a drug or [[Alcohol (drug)|alcohol]] problem, the attention in the household is on the parents rather than the child. This neglect of the child leads to the lowering of their self-esteem and helps develop a fantasy world in which they are in control. Hickey's Trauma Control Model supports how parental neglect can facilitate deviant behavior, especially if the child sees substance abuse in action.{{sfn|Hickey|2010|p=107}} This then leads to [[disposition]] (the inability to attach), which can further lead to homicidal behavior, unless the child finds a way to develop substantial relationships and fight the label they receive. If a child receives no support from anyone, then they are unlikely to recover from the [[psychological trauma|traumatic]] event in a positive way. As stated by E. E. Maccoby, "the family has continued to be seen as a major—perhaps ''the'' major—arena for socialization".{{sfn|Maccoby|1992|pp=1006–1017}}

====Chromosomal makeup====
There have been studies looking into the possibility that an abnormality with one's [[chromosome]]s could be the trigger for serial killers.<ref>{{Cite web|url=https://www.psychologytoday.com/blog/the-superhuman-mind/201803/do-all-serial-killers-have-genetic-predisposition-kill|title=Do All Serial Killers Have a Genetic Predisposition to Kill? – Exploring a Complex Question|website=Psychology Today|author=Berit Brogaard, D.M.Sci., Ph.D|year=2018|access-date=September 1, 2020|archive-date=September 7, 2020|archive-url=https://archive.today/20200907221522/https://www.psychologytoday.com/us/blog/the-superhuman-mind/201803/do-all-serial-killers-have-genetic-predisposition-kill|url-status=live}}</ref> Two serial killers, [[Bobby Joe Long]] and [[Richard Speck]], came to attention for reported chromosomal abnormalities. Long had an [[Klinefelter syndrome|extra X chromosome]].<ref name="speckpt">{{cite web|last1=Ramsland|first1=Katherine|title=Shame and the Serial Killer: Humiliation's influence on criminal behavior needs more attention|url=https://www.psychologytoday.com/us/blog/shadow-boxing/201909/shame-and-the-serial-killer|access-date=September 13, 2020|publisher=Psychology Today|archive-date=January 10, 2022|archive-url=https://archive.today/20220110004338/https://www.psychologytoday.com/us/blog/shadow-boxing/201909/shame-and-the-serial-killer|url-status=live}}</ref>  Speck was erroneously reported to have an [[XYY syndrome|extra Y chromosome]]; in fact, his [[karyotype]] was performed twice and was normal each time.<ref name="Engel 1972">{{cite journal |author=Engel, Eric |date=September 1972 |title=The making of an XYY |journal=Am J Ment Defic |volume=77 |issue=2 |pages=123–7 |pmid=5081078}}</ref> While attempts have been made to link the XYY karyotype to violence, including serial murder, research has consistently found little or no association between violent criminal behaviour and an extra Y chromosome.<ref name="March of Dimes">{{cite book |editor1=Robinson, Arthur |editor2=Lubs, Herbert A. |editor3=Bergsma, Daniel |year=1979 |title=Sex chromosome aneuploidy: prospective studies on children|series=Birth defects original article series '''15''' (1) |location=New York |publisher=[[John Wiley & Sons|Alan R. Liss]] |isbn=978-0-8451-1024-9}}
* {{cite book |editor=Stewart, Donald A. |year=1982 |title=Children with sex chromosome aneuploidy: follow-up studies |series=Birth defects original article series '''18''' (4) |location=New York |publisher=[[John Wiley & Sons|Alan R. Liss]] |isbn=978-0-8451-1052-2}}
* {{cite book |editor1=Ratcliffe, Shirley G. |editor2=Paul, Natalie |year=1986 |title=Prospective studies on children with sex chromosome aneuploidy |series=Birth defects original article series '''22''' (3) |location=New York |publisher=[[John Wiley & Sons|Alan R. Liss]] |isbn=978-0-8451-1062-1}}
* {{cite book |editor1=Evans, Jane A. |editor2=Hamerton, John L. |editor3=Robinson, Arthur |year=1991 |title=Children and young adults with sex chromosome aneuploidy: follow-up, clinical and molecular studies |series=Birth defects original article series '''26''' (4) |location=New York |publisher=[[John Wiley & Sons|Wiley-Liss]] |isbn=978-0-471-56846-9}}</ref>

====Fantasy====
Children who do not have the [[Power (social and political)|power]] to control the mistreatment they suffer sometimes create a new reality to which they can escape. This new reality becomes their [[Fantasy (psychology)|fantasy]] that they have total control of and becomes part of their daily existence. In this fantasy world, their emotional development is guided and maintained. According to Garrison (1996), "the child becomes [[Psychopathy#Sociopathy|sociopathic]] because the normal development of the concepts of right and wrong and [[empathy]] towards others is retarded because the child's emotional and [[Social change|social development]] occurs within his self-centered fantasies. A person can do no wrong in his own world and the pain of others is of no consequence when the purpose of the fantasy world is to satisfy the needs of one person" (Garrison, 1996). Boundaries between fantasy and reality are lost and fantasies turn to dominance, control, sexual conquest, and violence, eventually leading to murder. Fantasy can lead to the first step in the process of a dissociative state, which, in the words of Stephen Giannangelo, "allows the serial killer to leave the stream of consciousness for what is, to him, a better place".{{sfn|Giannangelo|1996|p=33}}

Criminologist Jose Sanchez reports, "The young criminal you see today is more detached from his victim, more ready to hurt or kill.  The lack of empathy for their victims among young criminals is just one symptom of a problem that afflicts the whole society."{{sfn|Tithecott|1997|p=38}} Lorenzo Carcaterra, author of ''Gangster'' (2001), explains how potential criminals are [[Labeling theory|labeled by society]], which can then lead to their offspring also developing in the same way through the [[cycle of violence]]. The ability for serial killers to appreciate the mental life of others is severely compromised, presumably leading to their dehumanization of others.<ref name="Silva-2004">{{harvnb|Silva|Leong|Ferrari|2004|p=790}}, {{harvnb|Tithecott|1997|page=43}}</ref> This process may be considered an expression of the [[intersubjectivity]] associated with a cognitive deficit regarding the capability to make sharp distinctions between other people and inanimate objects. For these individuals, objects can appear to possess animistic or humanistic power while people are perceived as objects.<ref name="Silva-2004"/> Before he was executed, serial killer [[Ted Bundy]] stated media violence and pornography had stimulated and increased his need to commit homicide, although this statement was made during last-ditch efforts to appeal his death sentence.{{sfn|Hasselt|1999|p=162}}

===Organized, disorganized, and mixed===
[[File:Ted Bundy headshot.jpg|thumb|150px|[[Ted Bundy]] in custody, Florida, United States, July 1978 (State Archives of Florida)]]

In the 1970s and 1980s, FBI profilers instigated a simple division of serial killers into "organized" and "disorganized"; that is, those who plan their crimes, and those who act on impulse.<ref>{{Cite journal |last= Cotter |first= P. |year= 2010 |title= The path to extreme violence: Nazism and serial killers |journal= [[Frontiers Media|Frontiers in Behavioral Neuroscience]] |volume= 3 |pages= Article 61, pp.&nbsp;1–5 |doi= 10.3389/neuro.08.061.2009 |doi-access= free |pmid= 20126638 |pmc= 2813721 }}</ref> The FBI's ''[[Crime Classification Manual]]'' now places serial killers into three categories: ''organized'', ''disorganized'', and ''mixed'' (i.e., offenders who exhibit organized and disorganized characteristics).{{sfn|Vronsky|2004|pp=99–100}}<ref name="PerperCina2010">{{cite book|author1=Joshua A. Perper|author2=Stephen J. Cina|title=When Doctors Kill: Who, Why, and How|url=https://books.google.com/books?id=WWJUGMh2OhcC&pg=PA51|year=2010|publisher=Springer Science & Business Media|isbn=978-1-4419-1371-5|page=51|access-date=September 1, 2020|archive-date=January 20, 2021|archive-url=https://web.archive.org/web/20210120053206/https://books.google.com/books?id=WWJUGMh2OhcC&pg=PA51|url-status=live}}</ref> Some killers descend from organized to disorganized as their killings continue,<ref name="PeckDolch2001">{{cite book|author1=Dennis L. Peck|author2=Norman Dolch|author3=Norman Allan Dolch|title=Extraordinary Behavior: A Case Study Approach to Understanding Social Problems|url=https://books.google.com/books?id=d9lIoA5jurUC&pg=PA253|year=2001|publisher=Greenwood Publishing Group|isbn=978-0-275-97057-4|page=253|access-date=September 1, 2020|archive-date=January 20, 2021|archive-url=https://web.archive.org/web/20210120053034/https://books.google.com/books?id=d9lIoA5jurUC&pg=PA253|url-status=live}}</ref> as in the case of [[Decompensation|psychological decompensation]] or overconfidence due to having evaded capture.

Organized serial killers often plan their crimes methodically, usually abducting victims, killing them in one place and disposing of them in another. They often lure the victims with ploys appealing to their sense of sympathy. Others specifically target prostitutes, who are likely to go voluntarily with a stranger. These killers maintain a high degree of control over the [[crime scene]] and usually have a solid knowledge of [[forensic science]] that enables them to cover their tracks, such as burying the body or weighing it down and sinking it in a river. They follow their crimes in the news media carefully and often take pride in their actions as if it were all a grand project.{{sfn|Ressler|Schachtman|1993|p=113}}

Often, organized killers have social and other interpersonal skills sufficient to enable them to develop both personal and romantic relationships, friends and lovers and sometimes even attract and maintain a spouse and sustain a family including children. Among serial killers, those of this type are in the event of their capture most likely to be described by acquaintances as kind and unlikely to hurt anyone. [[Ted Bundy]] and [[John Wayne Gacy]] are examples of organized serial killers.{{sfn|Ressler|Schachtman|1993|p=113}} In general, the [[Intelligence quotient|IQ]]s of organized serial killers tend to be normal range, with a mean of 98.7.<ref name="radfordfgcudb">{{cite web|title=Serial Killer Statistics|url=https://www.researchgate.net/publication/342501023|access-date=March 1, 2021}}</ref>

Disorganized serial killers are usually far more impulsive, often committing their murders with a random weapon available at the time, and usually do not attempt to hide the body. They are likely to be unemployed, a loner, or both, with very few friends. They often turn out to have a history of mental illness, and their [[modus operandi]] (M.O.) or lack thereof is often marked by excessive violence and sometimes [[necrophilia]] or sexual violence.<ref name="Serial Killers">{{cite web|url=http://www.enotes.com/forensic-science/serial-killers |title=Serial Killers |access-date=May 21, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090309132810/http://www.enotes.com/forensic-science/serial-killers |archive-date=March 9, 2009 }}</ref> Disorganized serial killers have been found to have a lower mean IQ than organized serial killers, at 89.4. Mixed serial killers, with both organized and disorganized traits, have an average IQ of 100.9, but a low sample size.<ref name=radfordfgcudb/>

===Medical professionals===
{{Main|Angel of mercy (criminology)}}
[[File:Kotobuki san'in court 19480616.png|thumb|Trial of [[Miyuki Ishikawa]] and her accomplices who killed infants born out of wedlock, 1948]]
Some people with a pathological interest in the power of life and death tend to be attracted to medical professions or acquiring such a job.<ref>{{harvnb|Hickey|2010|p=142}}</ref> These kinds of killers are sometimes referred to as "angels of death"<ref>{{cite journal|url=http://www.trutv.com/library/crime/notorious_murders/angels/index.html |title=Angels of Death |journal=New Scientist |volume=225 |issue=3007 |pages=40–43 |access-date=December 30, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20081218133027/http://www.trutv.com/library/crime/notorious_murders/angels/index.html |archive-date=December 18, 2008 |bibcode=2015NewSc.225...40W |last1=Wires |first1=Linda |year=2015 |doi=10.1016/S0262-4079(15)60268-8 |url-access=subscription }}</ref> or angels of mercy. Medical professionals will kill their patients for money, for a sense of sadistic pleasure, for a belief that they are "easing" the patient's pain, or simply "because they can".{{sfn|Holmes|Holmes|1998|p=204}} Perhaps the most prolific of these was the British doctor [[Harold Shipman]]. Another such killer was nurse [[Jane Toppan]], who admitted during her murder trial that she was [[Lust murder|sexually aroused by death]].<ref name="Female_Lust_Kill">{{cite web|title=When Women Kill Together |url=http://findarticles.com/p/articles/mi_go1613/is_1_16/ai_n29335603/ |first=Katherine |last=Ramsland |work=The Forensic Examiner |publisher=American College of Forensic Examiners Institute |date=March 22, 2007 |access-date=August 2, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20100829110653/http://findarticles.com/p/articles/mi_go1613/is_1_16/ai_n29335603/ |archive-date=August 29, 2010}}</ref> She would administer a drug mixture to patients she chose as her victims, lie in bed with them and hold them close to her body as they died.<ref name="Female_Lust_Kill"/>

Another medical professional serial killer is [[Genene Jones]]. It is believed she killed 11 to 46 infants and children while working at Bexar County Medical Center Hospital in San Antonio, Texas, United States.<ref name="biography.com-2012">{{cite web|title=Genene Jones Biography|url=http://www.biography.com/people/genene-jones-235417#criminal-background|url-status=dead|archive-url=https://web.archive.org/web/20120603170851/http://www.biography.com/people/genene-jones-235417|archive-date=3 June 2012}}</ref> She is currently serving a 99-year sentence for the murder of Chelsea McClellan and the attempted murder of Rolando Santos,<ref name="biography.com-2012" /> and became eligible for parole in 2017 due to a law in Texas at the time of her sentencing to reduce [[prison overcrowding]].<ref name="biography.com-2012" /> A similar case occurred in Britain in 1991, where nurse [[Beverley Allitt]] killed four children at the hospital where she worked, attempted to kill three more, and injured a further six over the course of two months. A 21st-century example is Canadian nurse [[Elizabeth Wettlaufer]], who murdered elderly patients in the nursing homes where she worked. William George Davis is another hospital nurse who was sentenced to death in Texas for the murder of four patients.<ref>{{Cite web|url=https://people.com/crime/texas-hospital-nurse-serial-killer-murdered-patients-with-ivs/|title=Murder in the ICU: Inside the Twisted Case of a Hospital Nurse Who Turned Out To Be a Serial Killer|website=Peoplemag|access-date=April 12, 2022|archive-date=April 12, 2022|archive-url=https://web.archive.org/web/20220412123130/https://people.com/crime/texas-hospital-nurse-serial-killer-murdered-patients-with-ivs/|url-status=live}}</ref>

===Female===
[[File:Las Pochianquis.jpg|thumb|Four Mexican sisters, known as ''[[Delfina and María de Jesús González|Las Poquianchis]]'', killed more than 150 people. [[Guinness World Records]] called them the "most prolific murder partnership".<ref>{{cite web|url=http://www.guinnessworldrecords.com/world-records/most-prolific-murder-partnership|title=Most prolific murder partnership|publisher=[[Guinness World Records]]|access-date=9 April 2018}}</ref>]]
Female serial killers are rare compared to their male counterparts.<ref name="Kelleher 1998 12">{{harvnb|Kelleher|Kelleher|1998|p=12}}, {{harvnb|Wilson|Hilton|1998|pp=495–498}}, {{harvnb|Frei|Völlm|Graf|Dittmann|2006|pp=167–176}}</ref> Sources suggest that female serial killers represented less than one in every six known serial murderers in the United States between 1800 and 2004 (64 females from a total of 416 known offenders), or that around 15% of U.S. serial killers have been women, with a collective number of victims between 427 and 612.<ref>{{harvnb|Hickey|2010|pp=187, 257, 266}}, {{harvnb|Vronsky|2007|p=9}}, {{harvnb|Farrell|Keppel|Titterington|2011|pp=228–252}}</ref> The authors of ''Lethal Ladies'', Amanda L. Farrell, Robert D. Keppel, and Victoria B. Titterington, state that "the Justice Department indicated 36 female serial killers have been active over the course of the last century."<ref name="Farrell">{{harvnb|Farrell|Keppel|Titterington|2011|pp=228–252}}</ref> According to ''The Journal of Forensic Psychiatry & Psychology'', there is evidence that 16% of all serial killers are women.<ref name="ReferenceA">{{harvnb|Newton|2006}}</ref>

Michael D. Kelleher and C. L. Kelleher created several categories to describe female serial killers. They used the classifications of ''[[wikt:black widow|black widow]]'', ''[[Angel of mercy (criminology)|angel of death]]'', ''sexual predator'', ''revenge'', ''profit or crime'', ''team killer'', ''question of sanity'', ''unexplained'', and ''unsolved''. In using these categories, they observed that most women fell into the categories of the black widow or team killer.<ref name="Frei"/> Although motivations for female serial killers can include attention seeking, addiction, or the result of psychopathological behavioral factors,<ref name="concordia1"/> female serial killers are commonly categorized as murdering men for material gain, usually being emotionally close to their victims,<ref name="Kelleher 1998 12"/> and generally needing to have a relationship with the victim,<ref name="Frei">{{harvnb|Frei|Völlm|Graf|Dittmann|2006|pp=167–176}}</ref> hence the traditional cultural image of the "black widow".

[[Image:Wuornos.jpg|thumb|150px|Highway sex worker [[Aileen Wuornos]] killed seven men in Florida between 1989 and 1990.]]
The methods that female serial killers use for murder are frequently covert or low-profile, such as murder by poison (the preferred choice for killing).<ref>{{harvnb|Wilson|Hilton|1998|pp=495–498}}, {{harvnb|Frei|Völlm|Graf|Dittmann|2006|pp=167–176}}, {{harvnb|Holmes|Holmes|1998|p=171}}, {{harvnb|Newton|2006}}</ref> Other methods used by female serial killers include shootings (used by 20%), suffocation (16%), stabbing (11%), and drowning (5%).<ref name="concordia1">{{cite book|url=http://www-psychology.concordia.ca/fac/Laurence/forensic/ProfileAnalysis1.ppt |title=Educated attempt to provide specific information about a certain type of suspect |publisher=Department of Psychology, Concordia University |format=PPT |year=2008 |access-date=July 1, 2010 |url-status=dead |archive-url=https://web.archive.org/web/20120426081443/http://www-psychology.concordia.ca/fac/Laurence/forensic/ProfileAnalysis1.ppt |archive-date=April 26, 2012}}</ref> They commit killings in specific places, such as their home or a health-care facility, or at different locations within the same city or state.<ref>{{harvnb|Vronsky|2007|pp=1, 42–43}}, {{harvnb|Schechter|2003|p=312}}</ref> A notable exception to the typical characteristics of female serial killers is [[Aileen Wuornos]],<ref>{{harvnb|Schechter|2003|p=31}}, {{harvnb|Fox|Levin|2005|p=117}}</ref> who killed outdoors instead of at home, used a gun instead of poison, and killed strangers instead of friends or family.<ref>{{harvnb|Schmid|2005|p=231}}, {{harvnb|Arrigo|Griffin|2004|pp=375–393}}</ref> One "analysis of 86 female serial killers from the United States found that the victims tended to be spouses, children or the elderly".<ref name="Frei"/> Other studies indicate that since 1975, increasingly strangers are marginally the most preferred victim of female serial killers,{{sfn|Vronsky|2007|p=41}} or that only 26% of female serial killers kill for material gain only.{{sfn|Hickey|2010|p=267}} Sources state that each killer will have her own proclivities, needs and triggers.<ref name="Wilson 1998 495–498">{{harvnb|Wilson|Hilton|1998|pp=495–498}}</ref><ref name="Frei"/> A review of the published literature on female serial murder stated that "sexual or [[sadistic personality disorder|sadistic]] motives are believed to be extremely rare in female serial murderers, and psychopathic traits and histories of childhood abuse have been consistently reported in these women."<ref name="Frei"/>

A study by Eric W. Hickey (2010) of 64 female serial killers in the United States indicated that sexual activity was one of several motives in 10% of the cases, enjoyment in 11% and control in 14% and that 51% of all U.S. female serial killers murdered at least one woman and 31% murdered at least one child.{{sfn|Hickey|2010|p=265}} In other cases, women have been involved as an accomplice with a male serial killer as a part of a serial killing team.<ref name="Wilson 1998 495–498"/><ref name="Frei"/> A 2015 study published in ''The Journal of Forensic Psychiatry & Psychology'' found that the most common motive for female serial killers was for financial gain and almost 40% of them had experienced some sort of mental illness.{{sfn|Harrison|Murphy|Ho|Bowers2015|pp=383–406}}

[[Peter Vronsky]] in ''[[Female Serial Killers]]'' (2007) maintains that female serial killers today often kill for the same reason males do: as a means of expressing rage and control. He suggests that sometimes the theft of the victims' property by the female "black widow" type serial killer appears to be for material gain, but really is akin to a male serial killer's collecting of totems (souvenirs) from the victim as a way of exerting continued control over the victim and reliving it.{{sfn|Vronsky|2007}} By contrast, Hickey states that although popular perception sees "black widow" female serial killers as something of the [[Victorian era|Victorian]] past, in his statistical study of female serial killer cases reported in the United States since 1826, approximately 75% occurred since 1950.<ref>[https://archive.today/20130215231752/http://www.erichickey.com/ Eric W. Hickey], (2010).</ref>
[[File:Alžbeta Bathory.jpg|thumb|150px|[[Kingdom of Hungary|Hungarian]] countess [[Elizabeth Báthory]] is thought to have murdered hundreds of young women]]
[[Elizabeth Báthory]] is sometimes cited as the most prolific female serial killer in all of history. Formally countess Elizabeth Báthory de Ecsed (Báthory Erzsébet in [[Hungarian language|Hungarian]], August 7, 1560 – August 21, 1614), she was a countess from the [[Báthory family]]. Before her husband's death, Elizabeth took great pleasure in torturing the staff, by jamming pins under the servant's fingernails or stripping servants and throwing them into the snow.{{sfn|Yardley|Wilson|2015|pp=1–26}} After her husband's death, she and four collaborators were accused of torturing and killing hundreds of girls and young women, with one witness attributing to them over 600 victims, though the number for which they were convicted was 80. Elizabeth herself was neither tried nor convicted. In 1610, however, she was imprisoned in the Csejte Castle, where she remained bricked in a set of rooms until her death four years later.{{sfn|Vronsky|2007|p=73}}

A 2010 article by Perri and Lichtenwald addressed some of the misconceptions concerning female criminality.<ref name="Perri">{{harvnb|Perri|Lichtenwald|2010|pp=50–67}}</ref> In the article, Perri and Lichtenwald analyze the current research regarding female psychopathy, including case studies of female psychopathic killers featuring [[Munchausen syndrome by proxy]], cesarean section homicide, fraud detection homicide, female kill teams, and a female serial killer.<ref name="Perri"/>

===Juvenile===
Juvenile serial killers are rare. There are three main categories that juvenile serial killers can fit into: primary, maturing, and secondary killers. There have been studies done to compare and contrast these three groups and to discover similarities and differences between them.{{sfn|Kirby|2009}} Although these types of serial killers are less common, oftentimes adult serial killers may make their debut at an early age and it can be an opportunity for researchers to study what factors brought about the behavior. While juvenile serial killers are rare, the youngest felon on death row is a juvenile serial killer named [[Harvey Miguel Robinson]] who was 17 at the time of his crimes and 18 at the time of his arrest.<ref>{{Cite web|url=https://www.psychologytoday.com/blog/shadow-boxing/201207/youngest-serial-killer-death-row|title=Youngest Serial Killer on Death Row|website=Psychology Today|access-date=March 2, 2018|archive-date=January 20, 2021|archive-url=https://web.archive.org/web/20210120053024/https://www.psychologytoday.com/us/blog/shadow-boxing/201207/youngest-serial-killer-death-row|url-status=live}}</ref><ref>{{Cite news |date=2021-01-21 |title=Harvey Robinson |url=https://teenkillers.org/juvenile-lifers/offenders-cases-state/pennsylvania-offenders/harvey-robinson/ |access-date=2022-03-27 |website=National Organization of Victims of Juvenile Murderers |archive-date=May 17, 2022 |archive-url=https://web.archive.org/web/20220517172407/https://teenkillers.org/juvenile-lifers/offenders-cases-state/pennsylvania-offenders/harvey-robinson/ |url-status=live }}</ref>

===Ethnicity and demographics in the United States===
<!-- NOTE: Refrain from adding too much information about one race and/or ethnicity, as to avoid bias and WP:UNDUE WEIGHT-->
[[File:Samuel Little.webp|thumb|150px|[[Samuel Little]] confirmed his involvement in at least 60 murders, the [[List of serial killers in the United States|largest number of confirmed victims]] for any serial killer in American history.<ref>{{cite news |last1=Lowery |first1=Wesley |last2=Knowles |first2=Hannah |last3=Berman |first3=Mark |date=November 30, 2020 |title=How America's deadliest serial killer went undetected for four decades |url=https://www.washingtonpost.com/graphics/2020/national/samuel-little-serial-killer/part-one/ |url-status=live |archive-url=https://web.archive.org/web/20201203025501/https://www.washingtonpost.com/graphics/2020/national/samuel-little-serial-killer/part-one/ |archive-date=December 3, 2020 |newspaper=[[The Washington Post]]}} Indifferent Justice Part 1: The Perfect Victim</ref> ]]
There is a myth that most serial killers are white males.<ref name="fbi.gov"/> However, according to the FBI, based on percentages of the U.S. population, white males are not more likely than other races to be serial killers.<ref name="fbi.gov"/> White males are actually greatly under-represented among serial killers in proportion to their overall numbers in the United States.<ref name="y076">{{cite book | last1=Walsh | first1=A. | last2=Jorgensen | first2=C. | title=Criminology: The Essentials | publisher=Sage Publications | year=2019 | isbn=978-1-5443-7539-7 | url=https://books.google.com/books?id=W-LFDwAAQBAJ&pg=PT291 | access-date=2024-05-21 | page=291}} "The reality is that white males are very much underrepresented among serial killers in proportion to their numbers in the population. Hickey (2006) claims that about 44% of serial killers operating from 1995 to 2004 have been African American, which is about 3.4 times greater than expected by the proportion of African Americans in the population. More recently, the Radford University's Serial Killer Information Center (Aamodt, 2016) found that since 2000 African Americans have been 59.8% of serial killers in the United States, whites 30.8%, Hispanics 6.7%, and Asian Americans 0.1%."</ref> According to a 2016 study, since the year 2000, African Americans accounted for roughly 60% of all serial killers in the United States.<ref name="y076" />

Anthony Walsh found that the prevalence of non-white serial killers has typically been drastically underestimated in both professional research literature and the mass media. Black males were over-represented among serial killers by a factor of 2.<ref name="t623">{{cite journal | last=Walsh | first=Anthony | title=African Americans and Serial Killing in the Media: The Myth and the Reality | journal=Homicide Studies | date=2011-11-28 | url=https://scholarworks.boisestate.edu/crimjust_facpubs/113/ | access-date=2024-05-21}} "There were many expressions of shock and surprise voiced in the media in 2002 when the “D.C. Sniper” turned out to be two Black males. Two of the stereotypes surrounding serial killers are that they are almost always White males and that African American males are barely represented in their ranks. In a sample of 413 serial killers operating in the United States from 1945 to mid-2004, it was found that 90 were African American. Relative to the African American proportion of the population across that time period, African Americans were overrepresented in the ranks of serial killers by a factor of about 2...The myth that serial killers are rarely African-Americans has had two detrimental effects. First, Whites tend to argue that Blacks are not sufficiently psychologically complex or intelligent to commit a series of murders without being caught. Second, police tend to neglect the protection of potential victims of serial killers in African-American communities. 1 table, 4 notes, and 64 references"</ref>{{sfn|Walsh|2005|pp=271–291}} Walsh argues that the popular media ignores black serial killers because of a fear of allegations of racism, and that this may enable black serial killers to operate more effectively, as their crimes do not get the same media attention as the crimes of non-black serial killers.<ref name="t623" />