In between the regular narration of the book that features the detective trying to figure out the case, there are sometimes chapters written from the perspective of the serial killer. These chapters usually are written anonymously and/or gender neutral so as to disguise which of the known characters in the book it is that is doing the killing.
These chapters frequently describe in great, loving detail how much they lust after the heroine (or other target) and can't wait to rape, torture, and then kill them. They also give detail as to what information the killer has on the investigators on the case.
- A variety of flashbacks in The Dark Knight Rises deal with the origin of Bane and an unnamed person he befriended in his prison. That person turns out to be Talia Al Ghul, the true leader of the League of Shadows who masterminded Bane's plan to control Gotham.
- Kiss the Girls, the film includes at least one voiceover monologue by Casanova, the unknown serial rapist/killer.
- Sherlock Holmes (2009) cuts between Sherlock's investigations and the many unnatural killings committed by the villain, all without revealing how or why he committed the murders.
- Lost Souls by Poppy Z. Brite
- The Healer by Frank G. Slaughter
- Pretty much every Jeffrey Deaver book has these.
- The Spenser novel "Crimson Joy" has one, not usual for the series.
- The "I will be called a murderer" chapters of Orhan Pamuk's My Name Is Red.
- Irvine Welsh' Filth has one of these, it turns out to be Narrator All Along for the protagonist.
- "Stone Cold" by Robert Swindells contains paragraphs written from the perspective of the murderer, Shelter.
- Dialogues of the Dead from Dalziel and Pascoe, a series of novels by Reginald Hill.
- The Surgeon, first book of the "Rizzoli & Isles" saga by Tess Gerritsen has interludes with the killer's thoughts. This is done in some of the other books in the series as well
- The Hercule Poirot story "The ABC Murders", explicitly marked as not being from Hastings' narrative. Subverted as he's only the Unwitting Pawn to the real murderer.
- Mary Higgins Clark often uses this tactic also, right until the final confrontation.
- Stephen King's The Dead Zone.
- Some of the Spilling series by Sophie Hannah have this.
- Alex Cross:
- Almost every book contains this, except for the ones where the killer's identity is known from the beginning.
- The movie Kiss the Girls starts with a voiceover by Casanova explaining his first twisted "relationship".
- Harry Potter and the Order of the Phoenix provides an in-universe example, wherein the title character has ominous dreams of some type of creature trying to break into a government facility. It turns out to be Voldemort's pet snake, Nagini, and the result of Harry's magical connection to the Dark Lord.
- John Sandford's Detective Lucas Davenport books (the Prey series) often switch the POV of chapters between Davenport and the latest serial killer to Prey on the Minneapolis St Paul area. Often the killer's POV chapters are highly disturbing, graphic, and bloody. But then again, so are Davenport's.
- The Reveal at the very end of Six Suspects is written by the killer. They don't reveal their name, but their identity is made obvious in the last few paragraphs.
- The DLC for Assassin's Creed: Syndicate features brief interludes where the player controls Jack the Ripper, long before his identity is revealed at the DLC's end.