Hybristophilia "is a paraphilia in which sexual arousal, facilitation, and attainment of orgasm are responsive to and contingent upon being with a partner known to have committed an outrage, cheating, lying, known infidelities or crime, such as rape, murder, or armed robbery." The term is derived from the Greek word ὑβρίζειν hubrizein, meaning "to commit an outrage against someone" (ultimately derived from ὕβρις hubris "hubris"), and philo, meaning "having a strong affinity/preference for". In popular culture, this phenomenon is also known as "Bonnie and Clyde Syndrome".
Many high-profile criminals, particularly those who have committed atrocious crimes, receive "fan mail" in prison which is sometimes amorous or sexual, presumably as a result of this phenomenon. In some cases, admirers of these criminals have gone on to marry the object of their affections in prison.
The reason why some people do this is unknown, but some speculations have been offered. For instance, Katherine Ramsland, who is a professor of forensic psychology at DeSales University mentions, that some of the women in particular who have married or dated male serial killers have offered the following reasons:
- "Some believe they can change a man as cruel and powerful as a serial killer."
- "Others “see” the little boy that the killer once was and seek to nurture him."
- "A few hoped to share in the media spotlight or get a book or movie deal."
- "Then there’s the notion of the “perfect boyfriend.” She knows where he is at all times and she knows he’s thinking about her. While she can claim that someone loves her, she does not have to endure the day-to-day issues involved in most relationships. There’s no laundry to do, no cooking for him, and no accountability to him. She can keep the fantasy charged up for a long time."
Others offered reasons along the lines of:
- "Some mental health experts have compared infatuation with killers to extreme forms of fanaticism. They view such women as insecure females who cannot find love in normal ways or as “love-avoidant” females who seek romantic relationships that cannot be consummated."
From a perspective focusing on male serial killers attracting female partners, Leon F. Seltzer (psychologist), has offered explanations based on evolutionary psychology. Serial killers, in his view, are cases of alpha males that tend to attract women. This is because such males were good at protecting women and their offspring in our evolutionary history. Women nowadays may consciously realize that it is unwise to date a serial killer, but they are nevertheless attracted to them, as he notes "as a therapist I've encountered many women who bemoaned their vulnerability toward dominant men who, consciously, they recognized were all wrong for them." As evidence of women's fantasy preference for dominant men, he refers to the book A Billion Wicked Thoughts: What the World's Largest Experiment Reveals about Human Desire by Ogi Ogas and Sai Gaddam. Seltzer discusses Ogas and Gaddam's argument that this fantasy is the dominant plot of most erotic/romantic books and movies written for women but the fantasy always holds that this male dominance is conditional, "it doesn’t really represent the man’s innermost reality." 
- One of the most infamous examples of hybristophilia is the large number of women attracted to Ted Bundy after his arrest. He often drew scores of women at the jammed courtrooms of his trials each day. Bundy allegedly received hundreds of love letters from women while he was incarcerated.
- Jeffrey Dahmer, a serial killer, is said to have had amorous women sending him letters, money, and other gifts during his time in prison.
- Serial killer Richard Ramirez married a female groupie in prison who had written him over 75 letters. During his trial, dozens of women flocked to the courtroom to catch a glimpse of him.
- Terrorists such as Anders Behring Breivik, Dzhokhar Tsarnaev, and Timothy McVeigh have also been the objects of hybristophilia.
- School shooters and other mass murders, such as Eric Harris and Dylan Klebold, James Eagan Holmes, and Adam Lanza have also been objects of hybristophilia.
- Famous author Ayn Rand is known to have been a hybristophile, having become infatuated with kidnapper and murderer William Edward Hickman after reading about him and admitted to basing aspects of several characters in her work on him.
- Hickey, [edited by] Eric W. (2006). Sex crimes and paraphilia. Upper Saddle River, N.J.: Pearson Education. pp. 197–9. ISBN 9780131703506.
- Ramsland, Katherine (20 April 2012). "Women Who Love Serial Killers". Psychology Today. Retrieved 13 May 2013.
- Seltzer, Leon F. (24 April 2012). "Why Do Women Fall for Serial Killers?". Psychology Today. Retrieved 13 May 2013.
- Gordon, Jr., Wilbert Anthony and James E. Elias. 2005. "Potentially Lethal Modes of Sexual Expression". Paper presented at the 2005 Western Region Annual Conference of the Society for the Scientific Study of Sexuality.
- Cawthorne, Nigel (2007). Serial Killers and Mass Murderers: Profiles of the World's Most Barbaric Criminals. Ulysses Press.
- Michaud, Stephen G. "The Only Living Witness: The True Story Of Ted Bundy". Crime Library.
- Barnard, Ian; Nanny M. W. de Vries, Jan Best. "The Racialization of Sexuality: The Queer Case of Jeffrey Dahmer". Thamyris Overcoming Boundaries: Ethnicity, Gender and Sexuality. Rodopi. p. 88. ISSN 13811312:2000::7:1-2:.
- Raymond Joseph Corsini. 1999. The Dictionary of Psychology. Psychology Press. ISBN 1-58391-028-X. p692.
- Prescott, Michael. "Romancing the Stone-Cold Killer: Ayn Rand and William Hickman", crime author Michael Prescott's website, ©2005.
- Sheila Isenberg: Women Who Love Men Who Kill, third edition, Backinprint.com 2000, ISBN 978-0-595-00399-0
- Jacquelynne Willcox-Bailey: Dream Lovers: Women Who Marry Men Behind Bars, Wakefield Press 1999, ISBN 978-1-86254-381-2
- Why are women drawn to men behind bars?, The Guardian, Monday 13 January 2003
- Women who have killer instincts, The Independent, 27 January 2005
- Liz O'Keefe: The partners of prisoners: Their reality, how they contribute to the criminal justice system and prisoner rehabilitation and how we can assist (PDF), paper presented at the Women in Corrections: Staff and Clients conference convened by the Australian Institute of Criminology in conjunction with the Department for Correctional Services South Australia, 31 October-1 November 2000, Adelaide, Australia