Photographs and pictures appear repeatedly throughout the novel. Joe describes a picture frame cutting Jeremy when they are boys. Lila’s rape is documented in a photo, in which her attackers' faces are scrambled. The crime scene photos of Crystal’s murder are integral to Lila and Joe’s investigation. Even the first hint of Carl’s innocence comes from a photo, when Joe sees a picture of Carl getting arrested and notes that he looks confused. However, a visual image doesn’t always paint the full picture—as is the case with the photograph of Lila’s attack. The photos also speak to how emotionally impactful visual imagery is, as seen with Joe’s reaction to the crime scene images. Human reactions to visuals can be visceral and emotionally charged. This also speaks to the contextual significance of Eskens’s including the Vietnam War, a conflict that came to be symbolized by several grotesque war images.  

A murder mystery is a puzzle by nature, and Joe refers to Carl's case as a puzzle on multiple occasions. Joe perceives his discussions with Carl as a puzzle, gathering pieces to construct the “monster” who Joe initially sees. There is also the spot-the-difference puzzle of the crime scene photos and the puzzle of Crystal’s coded diary; the latter puzzle's solution requires Jeremy's adept pattern recognition skills.