LitCharts assigns a color and icon to each theme in The Da Vinci Code, which you can use to track the themes throughout the work.
Conspiracies and Secrets
Art and Symbolism
Faith vs. Knowledge
Sacred Femininity and Revisionist History
Power and Manipulation
Summary
Analysis
Langdon waits in the restroom, just as Sophie’s strange voicemail instructed. Sophie enters, saying there’s not much time. She tells Langdon he is under surveillance cachée, a DCPJ tactic where suspects are invited to a crime scene in the hope they will incriminate themselves. As proof, Sophie directs Langdon to the GPS tracker Collet placed in his pocket at the hotel. She insists he keep it on his person, lest Fache realize Langdon knows he’s being watched. Langdon can’t believe Fache thinks he killed Saunière, but Sophie produces her own photo of the crime scene, which was uploaded to the Cryptology Department earlier that night. Fache intentionally erased the last line of Saunière’s message: “P.S. Find Robert Langdon.”
Sophie’s knowledge of Fache’s suspicions and habits motivates her to help Langdon, though her reasons for doing so are unclear. The GPS tracker is undeniable proof that Fache is keeping tabs on the symbologist. Saunière’s full message explains the captain’s suspicion, as it names Langdon directly. Fache’s deliberate erasure of this part of the message and the practice of surveillance cachée are themselves a kind of conspiracy designed to catch criminals.