How Genetic Genealogy Is Rewriting the Rules of Cold Case Investigation
For decades, cold cases represented the limits of forensic science. Evidence sat in lockers. Families waited for answers that never came. Killers aged into anonymity, secure in the belief that time was on their side.
That’s no longer true.
Since 2018, forensic genetic genealogy has fundamentally transformed cold case investigation. The breakthrough came with the Golden State Killer arrest—a serial murderer and rapist who had evaded capture for over 40 years, finally identified through DNA uploaded to a public genealogy database.
How It Works
Traditional DNA testing requires an exact match. If your suspect isn’t in CODIS (the FBI’s criminal DNA database), you get nothing.
Genetic genealogy takes a different approach. Instead of looking for the killer directly, investigators look for his relatives.
Crime scene DNA is uploaded to public genealogy databases like GEDmatch. The database returns genetic matches—third cousins, fourth cousins, distant relatives who’ve taken consumer DNA tests. Genetic genealogists then build family trees backward, tracing these connections through census records, obituaries, and birth certificates until they find where the trees intersect.
Somewhere in that intersection is the suspect.
The Numbers Tell the Story
Since 2018, genetic genealogy has helped solve hundreds of cold cases across the United States. Victims who waited decades for justice are finally getting answers:
– **April Tinsley** (1988) – Solved after 30 years
– **Marcia King, the “Buckskin Girl”** (1981) – Identified after 37 years
– **Mary Schlais** (1974) – Solved after 50 years
These aren’t just statistics. They’re daughters, sisters, mothers. People who deserved answers.
The Evidence Was Always There
What’s remarkable about many of these cases is that the evidence existed all along. DNA samples preserved in the 1980s and 1990s—too degraded or too small for the technology of their time—are now being successfully analyzed.
The science caught up.
For families still waiting, there’s reason to hope. If the evidence was preserved, if the DNA is there, the answer may be waiting to be found.
The cases aren’t cold anymore. They’re just waiting for the right technology.
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Crime Decoded explores how forensic science and genetic genealogy bring justice to victims and closure to families. Subscribe wherever you listen to podcasts.