Season 5 · Episode 25
Zodiac Killer: The Cipher Years and the Bus Bomb Threat
25 February 2026·1:03:16
Listen
Show Notes
In the weeks after Paul Stine’s murder, the Bay Area waited for the next strike—but what came next wasn’t a confirmed attack. Instead, the Zodiac launched a long, unnerving campaign of letters, ciphers, and threats that kept the region in fear for years.
In Episode 7, “The Cipher Years,” we track the communications that defined the next phase of the case: the Dripping Pen card, the infamous Z340 cipher, shifting “scorecards,” and messages that escalated from taunting investigators to threatening mass harm.
We also examine major flashpoints from 1969–1970: the letter to celebrity attorney Melvin Belli, the disputed abduction of Kathleen Johns, the “My name is—” cipher, the Mount Diablo map, the “Little List” letter, and the chilling Halloween card sent to journalist Paul Avery.
This is the story of how the Zodiac may have paused his confirmed killings—but never stopped trying to control the narrative.
00:00 After Stine Fear
01:06 Dripping Pen Card
01:58 Z340 Cipher Arrives
34:43 Building Trust First
36:55 Assembling the Review Team
37:53 Forensic Rethink and DNA
41:23 AI Promise and Pitfalls
42:51 Suspects and Linked Crimes
44:25 Science in the Field
51:31 Why Murders Get Solved
54:21 Assumptions and Outliers
55:51 Managing Media Tip Floods
01:01:36 Ego Games and Wrap Up
Next episode: the investigation itself—how multiple agencies coordinated, what evidence they had, and why an arrest never came.
The Robert Black Murders mentioned in this episode can be found in season 1 Episodes 3-8
You can buy the books mentioned in the podcast's by clicking the links below
Tom's Best Selling Book:
Ruxton: The First Modern Murder Paperback Edition
Ruxton: The First Modern Murder Kindle Edition
Simon's Best Selling Book:
The Ten Percent Paperback Edition
The Ten Percent Kindle Edition
Our Website: https://crimetimeinc.com/
If you like this show please leave a review. It really helps us.
Please help us improve our Podcast by completing this survey.
http://bit.ly/crimetimeinc-survey
zodiac killer, zodiac cipher years, z340 cipher, dripping pen card, melvin belli zodiac letter, kathleen johns zodiac, mount diablo map, paul avery halloween card, zodiac killer letters, zodiac killer timeline
About Crime Time Inc.
Season 5 of Crime Time Inc. broadens its reach across two sides of the Atlantic.
This season features cases from Scotland and across the wider UK — rooted in real investigative experience — alongside deep dives into some of the most infamous murder cases in American history.
Hosted by former detectives Simon and Tom, with experience in both the UK and the United States, including time working alongside the FBI, the show strips away sensationalism to explain how crime and justice really work.
Two crime worlds. One podcast.
New episodes released regularly throughout the season.
Our Website: https://crimetimeinc.com/
If you like this show please leave a review. It really helps us.
Please help us improve our Podcast by completing this survey.
http://bit.ly/crimetimeinc-survey
Hosted on Acast. See acast.com/privacy for more information.