Because Aristotle said so

"(I)t is an instinct of human beings, from childhood, to engage in mimesis (indeed, this distinguishes them from other animals: man is the most mimetic of all, and it is through mimesis that he develops his earliest understanding); and equally natural that everyone enjoys mimetic objects. A common occurrence indicates this: we enjoy contemplating the most precise images of things whose actual sight is painful to us, such as the forms of the vilest animals and of corpses. The explanation of this too is that understanding gives great pleasure not only to philosophers, but likewise to others, too ..."

— Aristotle, Poetics

Now, just tell me that this guy would not have been fascinated by crime fiction.

© Peter Rozovsky 2008