As a genre, the serial killer murder mystery is as artificial as Agatha Christie. Real life serial killers don't take their inspiration from the Book of Leviticus (or whatever.) They don't pit their enormous intellects against the police.
Real life serial killers are demented low-lifes. Psychopaths as brilliant as Hannibal Lecter is supposed to be don't go on killing sprees; they set up their own businesses or go into politics.