Necrophilia

A paraphilia, necrophilia (also known as "thanatophilia" and "necrolagnia") is a sexual attraction to the dead, the word being derived from the Ancient Greek terms νεκρός (nekros; "corpse," or "dead") and φιλία (philia; "friendship"). Motivations for necrophilia, which is often tied to low self-esteem, include the loss of a loved one and the want to reunite with them, the desire for complete control over an unresisting partner, a socially isolated individual finding comfort in the act or simple lust. The act of having sex with a corpse is a misdemeanor or felony in most regions.

Criminal Minds
The Mill Creek Killer ("The Last Word") would drag the bodies of his victims into the woods, occasionally returning to the dump site to groom and perform sexual acts with the corpses. Roderick Gless ("Cold Comfort") abducted women and embalmed them alive, having sex with their preserved bodies afterward.

Real World

 * Jeffrey Dahmer
 * Ed Gein
 * Carl Tanzler