Tremors in the Blood: Murder, Obsession, and the Birth of the Lie Detector

Image of Tremors in the Blood: Murder, Obsession, and the Birth of the Lie Detector
Release Date: 
March 7, 2023
Crooked Lane Books
Reviewed by: 

“Brightly written and well-researched, this book will appeal immensely to true-crime fans.”

Long ago, the British author Daniel Defoe said, “There is a tremor in the blood of a thief.” If that’s so, maybe a person’s blood pressure rises while lying. Wouldn’t it be great to concoct a machine to measure it all?

It happened in Berkeley, CA, in the 1920s.

Three men—a visionary police chief, a rookie cop with a PhD in physiology, and a teenage magician—created a machine that could reveal whether someone was being truthful. It was called a lie detector.

In Tremors in the Blood, Wired senior editor Katwala tells the fascinating story of the controversial apparatus, its unlikely inventors, and the many early efforts to prove its accuracy in criminal cases.

The key inventor was John Larson, the rookie cop whose graduate education made him a standout on a California police force filled with dropouts and extortionists. Larson’s master’s thesis was on the new technology of fingerprint identification, which had become admissible in court.

He thought there might be still more ways to catch criminals.

Larson’s boss, celebrated police chief August Vollmer, always searching for ways to improve policing, had read an academic paper by a psychologist who tested whether friends were lying based on their blood pressure readings. He asked rookie Larson to come up with a machine that could do the same thing.

Wags ridiculed the resulting apparatus—but the damned thing seemed to work. It helped identify the perpetrator of a theft in a women’s dorm at Berkeley.

The third man who helped develop the lie detector was the young magician Leonarde Keeler, who grew deeply intrigued by the emotograph, as he called the machine, and became Larson’s assistant.

Soon enough, the lie detector suffered its first public failure. It exonerated one Henry Wilkens, a mechanic, of his role in the death of his wife—a major case examined in the book. But by then, magician Keeler, something of a loose cannon, had taken the lie detector out of the courtroom and begun spreading its wonders into disparate corners of life in the U.S. and abroad.

Keeler’s idea of improving the lie detector involved using “cheap parlor tricks” that created sensations and hindered John Larson’s hopes of winning scientific acceptance for the machine. The co-inventors would clash for years, with Larson working to prevent Keeler from introducing testing into politics and business (where it was used to detect employee thieves).

Much of Tremors in the Blood focuses on criminal cases in which the lie detector is applied, with mixed success, underscoring the unreliability of the technology. The author’s absorbing accounts of crimes and lie detector tests will keep readers turning pages.

Katwala explains that lie detectors don’t work. But people think they do, and they have long been used by police and prosecutors in criminal prosecutions.

“There is no single tell-tale sign of deception that holds true for everyone—no Pinocchio’s nose,” he writes. Indeed, more than 200 people who failed a lie detector test—leading to conviction and imprisonment for a crime—were later found to be innocent.

“The lie detector refuses to die,” writes the author. The latest forms of the technology are based on brain scans and artificial intelligence.

Brightly written and well-researched, this book will appeal immensely to true-crime fans.