Chapter summaries Shadow of Doubt Brad Thor

Chapter 24 Summary: Brunelle’s AI Surveillance Breakthrough

Spoiler Notice

This summary and analysis of Shadow of Doubt Chapter 24 contains key plot developments, including the use of algorithmic video surveillance to identify a suspect in Jean-Jacques Jadot’s murder. If you have not yet read the chapter, proceed with caution.

Complete Chronological Summary

The chapter opens with Brunelle bringing halal food to MoMo, who is still struggling to crack the flash drive encryption. She reminds him that La Crim has already unlocked the victim's iPhone, but MoMo dismisses that as a simple six‑digit password. Brunelle’s mood is sour from lack of sleep—heavy thunderstorms kept her awake, and earlier Gibert had suggested a drink to “clear the air,” which she refused, telling him to get over his guilt. After the storms let up around 5 a.m., she emailed her boss to say she would follow a lead and then managed a few hours of sleep. She arrived at DGSI headquarters after four coffees, trying to be polite.

Despite her irritation, she agrees to fetch MoMo’s lunch. While returning, she decides that if MoMo cannot crack the drive by day’s end, she will hire outside hackers—without official approval, since she removed the flash drive from the crime scene. Back at her desk, she reads a text from Gibert: his officers canvassed rooftops near Jadot’s apartment. One resident heard a heavy thud on the night of the murder, but she was listening to an audiobook and couldn’t be sure it was a person. A roof search and new CCTV footage yielded nothing.

Suddenly, an idea strikes Brunelle. She returns to MoMo and asks about the Depeche Mode concert at the Accor Arena where France tested Algorithmic Video Surveillance (AVS). MoMo confirms DGSI has access, but notes the AI’s gait recognition capability is legally restricted to sports, recreational, and cultural venues. Brunelle hypothesizes the killer used the rooftops, specifically hiding in the National Archives (a cultural venue) before the murder, then crossing over to Jadot’s building. MoMo agrees to run the AI as a “practice exercise” for a fictional bomb suspect, with the understanding that results will be deleted and not used to violate rights.

They access the National Archives’ CCTV cloud and set the AI to search. The software processes faces, clothing, objects, and gait. The AI flags two anomalies: one person entered Sunday but never left; another left Monday but never entered. Both avoid cameras, making facial recognition impossible, so the AI defaults to gait comparison. Brunelle watches footage of the exiting figure walking with a slight limp. She declares he is faking it—by putting a rock in his shoe. MoMo reluctantly agrees it could fool the AI. They track the limping man to 1 Rue de Chapon, where he disappears inside. Brunelle immediately calls Gibert, texting him the address and telling him to bring a flashlight.

Key Events

  • Brunelle pressures MoMo to decrypt the flash drive; she contemplates hiring private hackers if he fails by day’s end.
  • She learns a neighbor heard a heavy thud on the roof near Jadot’s apartment during the murder.
  • Brunelle devises a theory: the killer hid in the National Archives, used the rooftop to access Jadot’s window, then returned to the archives before leaving Monday morning.
  • MoMo agrees to repurpose the AVS software as a training exercise to bypass legal restrictions.
  • The AI identifies two matching figures—one who entered but never left, and one who left but never entered—detected primarily by gait.
  • Brunelle spots the departing suspect faking a limp; MoMo confirms the ruse could evade gait recognition.
  • They trace the suspect to 1 Rue de Chapon, and Brunelle alerts Gibert to meet her there.

Character Development

Brunelle demonstrates persistence and creative problem‑solving despite exhaustion. Her willingness to bend rules (hiring outside hackers, using AVS outside its intended parameters) reveals a pragmatic, ends‑justify‑the‑means mindset. She also shows emotional control: she resists the urge to choke MoMo and later forgives his irritation, focusing on the investigation. Her confrontation with Gibert over their “tension” reinforces her resolve to avoid personal entanglement.

MoMo remains technically competent but cautious about legal boundaries. He agrees to help only after constructing a plausible “training” pretext, indicating a respect for procedure that Brunelle lacks. His skepticism about Brunelle’s hypothesis (“pretty wild”) gives way to cooperation, showing his trust in her instincts.

Gibert (off‑page) is shown as still trying to repair his relationship with Brunelle after his earlier guilt. His officers’ canvass work—though fruitless—keeps him involved in the case, though Brunelle’s new lead places her steps ahead of La Crim.

Themes, Symbols, or Motifs

  • Surveillance and its limits: The chapter contrasts the power of AI gait recognition with the legal and ethical constraints that prevent its full use. Brunelle’s workaround (a “practice exercise”) highlights the tension between security and civil liberties.
  • Deception and camouflage: The killer’s methods—using the archives as a hideout, faking a limp, avoiding cameras—underscore the theme that even advanced technology can be fooled by human ingenuity. Brunelle’s insight about a rock in the shoe shows her understanding of practical counter‑measures.
  • Exhaustion as a character force: Brunelle’s sleep deprivation drives her irritability and perhaps her risk‑taking. Her multiple coffees symbolize her reliance on stimulants to maintain her edge, a motif seen in earlier chapters.
  • The rooftop as a liminal space: The killer’s path across roofs and through the archives blurs public and private, visible and hidden. This physical route mirrors the psychological boundary‑crossing Brunelle herself performs by repurposing restricted software.

Why This Chapter Matters

Chapter 24 marks a turning point in the investigation: Brunelle moves from reactive analysis (waiting for MoMo to crack the drive, following CCTV leads) to a proactive, hypothesis‑driven approach. By leveraging a cutting‑edge AI system in a legally gray manner, she gains a tangible suspect and location. The adoption of gait recognition as a plot device modernizes the thriller’s forensic toolkit and raises stakes around data privacy. The chapter also deepens Brunelle’s character as a rule‑bending but effective operative, setting up ethical dilemmas likely to resurface later. Finally, the address at 1 Rue de Chapon provides a concrete target for the next chapter, escalating the manhunt.

Study Questions and Answers

  1. What legal restriction does MoMo cite when Brunelle first asks to use the AVS gait recognition?
    The AVS software is legally allowed only at sports, recreational, and cultural venues to prevent public order offenses. MoMo notes that using gait recognition beyond those parameters would violate the National Assembly’s rules.

  2. Why does Brunelle believe the killer faked a limp?
    She explains that a person can put a small object like a rock in their shoe, which forces a consistent, unnatural gait. The brain does not need to consciously maintain the limp, so it does not revert to the person’s normal stride—thus fooling the AI’s gait recognition.

  3. How does MoMo justify running the AI search on the National Archives’ CCTV footage?
    He frames it as a “practice exercise” for DGSI officers to better understand the software, using a fictional bomb suspect at the archives. He insists that none of the results be used to violate anyone’s rights, and that all data will be deleted afterward.

Navigation Links