Hybristophilia is a paraphilia involving being sexually aroused by people who have committed crimes; in particular cruel or outrageous crimes.
The sexologist John Money defines hybristophilia as:
"a paraphilia of the marauding/predatory type in which sexuerotic arousal and facilitation and attainment of orgasm are responsive to and contingent on being with a partner known to have committed an outrage or crime, such as rape, murder, or armed robbery"
Many high-profile criminals, particularly those who have committed atrocious crimes, receive fan mail in prison, 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. An example of this is Ted Bundy who is known to have received about two hundred fan letters each day from female admirers.