Terminal Velocity Chapter 22 Summary: The Advertising ID Lead
⚠️ Spoiler Warning: This guide contains detailed spoilers for the entire novel. Proceed only if you've finished reading or are comfortable knowing the plot.
Summary
In Chapter 22, the investigation into the Hunt family murders moves to Clarkston, Washington. FBI Special Agent Mandy Cobb and tech consultant Gavin Biery meet with Sheriff Whitcomb and his colleague Dot to review crime-scene evidence. During a pizza lunch, Gavin reveals a new lead: he purchased the advertising ID for the Hunts’ zip code and discovered that someone had recently targeted Maddie Hunt’s data through a Tor browser. His homegrown AI tool, Princess, traced the Tor browser’s IP address to the Tri-Cities area of central Washington. That same IP address overlaps with an earlier trace to India, suggesting encrypted communication between the killers and a person in South Asia. Mandy, initially skeptical, realizes the killer used digital surveillance to track the family’s movements. The team concludes the Hunt murders were a sophisticated, multi-person hit. The chapter ends with Mandy directing Gavin to use Princess to find a specific address in the Tri-Cities.
Key Events
- Gavin Biery joins Mandy, Sheriff Whitcomb, and Dot for a pizza lunch at Fazzari’s in Clarkston; he grudgingly admits the pizza rivals New York.
- Gavin explains that he analyzed Maddie Hunt’s cell-phone data and found a new lead: an advertising ID purchased for the Hunts’ zip code.
- The purchase was made through a Tor network, which anonymizes users. Gavin’s AI “Princess” traced the Tor browser’s IP back to the Tri-Cities area.
- Mandy reveals that the FBI’s Digital Media Exploitation group at Hoover has not made progress on the India IP lead, leaving her frustrated.
- Gavin connects the dots: the same IP address used for the Tor browser also appeared in the India link, implying encrypted communication.
- The team discusses how the killer could have tracked the family’s cell phones to lure Cole Hunt into the barn without a struggle.
- Sheriff Whitcomb presses for the link to military-style weapons; Mandy argues the ballistics evidence and digital tracking point to a professional hit.
- The chapter closes with Mandy asking Gavin to deploy Princess to pinpoint an address in the Tri-Cities.
Character Development
Mandy Cobb – Mandy’s reliance on traditional FBI channels (Hoover’s DMX group) is shaken when Gavin outperforms them. Her internal conflict grows: she must trust an outsider whose methods are unconventional but effective. Her past experience with the CTAPU fly team makes her wary of over-reliance on digital clues, yet she adapts.
Gavin Biery – Gavin’s confidence in his own technical skills is on full display. He explains complex concepts (Tor, advertising IDs, AI) to local law enforcement without condescension. His pride in his homemade AI “Princess” mirrors his resourcefulness and independence from the Bureau.
Sheriff Whitcomb – The sheriff maintains local authority while leveraging federal resources. He is patient, methodical, and focused on actionable facts, pushing back when theories seem too speculative (e.g., the India-Pakistan conspiracy). His dog Luna humanizes him.
Dot – Dot provides local color and common-sense questions, acting as the reader’s surrogate. Her banter with Gavin about pizza and her query about the Tor network help explain technical details to the audience.
Themes, Symbols, or Motifs
Digital Surveillance as a Double-Edged Sword – The same advertising IDs that companies use to target consumers are repurposed by the killer to track the Hunt family. Gavin purchases the same data for investigative purposes, highlighting how digital footprints can both threaten and serve justice.
The Onion Router (Tor) and Anonymity – The Tor network symbolizes the modern arms race between privacy and law enforcement. The killer’s use of Tor suggests a sophisticated threat, yet Gavin’s AI manages to pierce part of the veil.
Small‑Town vs. Federal Authority – The Clarkston setting contrasts with the FBI’s Washington D.C. apparatus. Sheriff Whitcomb’s jurisdictional concern and his willingness to collaborate reflect the friction and cooperation between local and federal investigations.
Trust in Non‑Traditional Expertise – Mandy’s initial skepticism of Gavin’s methods gives way to grudging respect. The chapter underscores that effective investigations often require combining institutional resources with unconventional talent.
Why This Chapter Matters
Chapter 22 marks a pivotal shift in the investigation. Gavin’s advertising-ID breakthrough provides the first concrete geographical lead since the crime. The connection between the Tri‑Cities IP and the India router suggests a transnational conspiracy behind the Hunt murders. Mandy’s decision to turn to Gavin—rather than wait for Hoover—signals her growing independence and willingness to adapt. The chapter sets up the next leg of the investigation in Washington’s Tri‑Cities region and deepens the mystery of who hired the killers and why.
Study Questions and Answers
1. What technical method does Gavin use to locate the killer, and why is the Tor network a challenge?
Gavin buys the advertising ID for the Hunts’ zip code, then traces who purchased that data. The killer used a Tor browser, which routes data through multiple encrypted nodes (like an onion’s layers) to hide the user’s IP address. Gavin’s AI “Princess” nevertheless found a digital footprint by analyzing data paths, leading back to a server in the Tri‑Cities.
2. Why is Mandy initially frustrated with the FBI’s DMX group, and how does that affect her view of Gavin?
Mandy expected Hoover’s Digital Media Exploitation experts to outperform Gavin, but they could not progress beyond the India IP address. Gavin, however, produced a new lead using the advertising ID and his AI. This frustrates Mandy because it forces her to acknowledge that her own agency’s resources are less effective than Gavin’s unconventional approach.
3. How does the chapter connect the digital evidence to the physical crime scene?
Gavin’s advertising-ID trace shows that the killer could see Maddie Hunt’s daily movements (school, soccer field, home). Combined with the cut data lines to the Hunt house, the team infers that the killers used that surveillance to ambush the family in the barn and then wait for Cole to return from his meeting. The ballistics evidence of suppressors and contact shots supports the conclusion that this was a professionally planned hit.