Serial killers held a convention in Neil Gaiman's The Sandman: The Doll'sHouse but their invited Guest of Honor, the Family Man, was unable to attend because he was too busy fighting John Constantine in Jamie Delano's Hellblazer and the Bogey Man did not attend because Alan Moore's Swamp Thing had killed him. It seems that the Corinthian, a nightmare escaped from the Dreaming, initiated and inspired serial killing.
Alan Moore and Grant Morrison each wrote a comic strip about a real serial killer. Grant Morrison and Ian Rankin each wrote a work of fiction about the real serial killer, Bible John.
Finally, Alan Moore created John Constantine in Swamp Thing while both Neil Gaiman and Ian Rankin have written about Constantine. Although Constantine has caused many deaths, he is not himself a serial killer and in fact made it his business to put the Family Man out of business.