Genetic Detectives: How Genealogy Exposed Hidden Killers

The Golden State Killer, Wrongful Convictions, and the DNA Revolution That Solved Forty-Year-Old Murders

By: Julian Maddox

Narrated by: Virtual Voice

Second Edition — Completely Rewritten and Expanded

They uploaded their DNA to find their ancestors. It found a killer instead.

This fully revised Second Edition of Genetic Detectives expands the original three-case volume into a comprehensive twelve-case investigation into forensic genetic genealogy — the technique that has transformed cold case investigation since 2018 — completely rewritten from the ground up, with new cases, new research, and new analysis of a method still reshaping the boundaries of criminal justice.

The Golden State Killer committed at least fifty rapes and thirteen murders across California and spent thirty years living quietly in a Sacramento suburb, confident the trail had gone cold. The DNA had never gone cold. It had simply been waiting for the right database to exist — a database built not by law enforcement, but by millions of ordinary people submitting saliva samples to trace their family histories. When investigators uploaded his DNA to that database in 2018, the partial matches it returned led, through genealogical research, to a name. It took months. It ended a forty-year manhunt.

That technique — forensic genetic genealogy, or IGG — has since identified hundreds of suspects across the United States and beyond. It has convicted serial killers and rapists who had evaded justice for decades. It has freed innocent people imprisoned for crimes they did not commit. And in cases like the Zodiac Killer, it has demonstrated, with uncomfortable clarity, that even the most powerful forensic tool has limits.

Twelve landmark cases, fully rewritten — including:

• The Golden State Killer — how Barbara Rae-Venter's genealogical technique ended a forty-year manhunt through the DNA of distant cousins who had never heard of Joseph DeAngelo
• The first IGG conviction — the Talbott trial, where a jury evaluated forensic genetic genealogy as evidence for the first time in history and returned a unanimous guilty verdict
• Angie Dodge — how IGG identified the real killer and freed the innocent man who had spent twenty years in prison for her murder
• The Bear Brook murders — four victims in sealed drums in a New Hampshire forest, and the case that proved the technique worked before the Golden State Killer made it famous
• The Christine Jessop case — how a Canadian cold case was solved through an American database, identifying a killer who had died five years before his name was spoken
• The Zodiac Killer, Lori Erica Ruff, Rex Heuermann, and five more cases that map the full range of what the technique can do — and where it reaches its limits

Drawing on court documents, forensic science publications, and the accounts of the genealogists who built the family trees, Genetic Detectives (Second Edition) is a work of narrative non-fiction that follows the science from its origins to its most recent applications — and asks what it means to live in a world where your ancestors' curiosity about their family history may one day identify a criminal who shares your DNA.

From the author of The Silent Witness and Forgotten Victims.

Perfect for readers of Michelle McNamara, Kate Summerscale, and Paul Holes.