Season 5 · Episode 31
Zodiac Killer Suspect Arthur Leigh Allen: The Evidence, the Doubts & the Unanswered Questions | Episode 9 Part 2
12 March 2026·38:25
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Show Notes
In this episode, we review the case made against Arthur Leigh Allen, the man long considered by many to be the leading suspect in the Zodiac Killer investigation.
Tom and Simon break down the strongest points pointing toward Allen, including his proximity to key crime scenes, his familiarity with coded messages, witness identification, shoe size, violent behaviour, and the disturbing testimony that he taught children how to create and decipher codes.
But this episode also focuses on the evidence that muddies the picture. The discussion explores the disputed fingerprint and palm print evidence, the limits of the handwriting analysis, the problems with partial DNA from the Zodiac letters, and how easily investigators can become locked onto one suspect while dismissing contradictions.
The conversation also looks at Allen’s background in the US Navy, his psychiatric history, his conviction for offences against a child, and the importance of building a proper timeline around his movements, incarceration, communications, and behaviour.
Tom raises key investigative questions:
What exactly was Allen treated for psychiatrically, and when?
What did he actually do during his Navy service?
Why were some potentially incriminating items found, but no firearms, ammunition, or clear cryptographic material?
Was too much weight placed on forensic evidence that may have been contaminated, incomplete, or misunderstood?
The episode also examines the role of Don Cheney, asking whether he should have been treated more seriously as a suspect or at least as a critical line of inquiry.
This is a detailed look at how cold case reviews should be approached: start at the beginning, separate fact from theory, revisit early witness statements, and resist the temptation to force the evidence to fit the favourite suspect.
If you are fascinated by the Zodiac case, suspect profiling, forensic ambiguity, and the psychology of major investigations, this is an essential listen.
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.
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