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To Solve a Cold Case, French Police Bent DNA Privacy Law

12 August 2026 · 25m

Across the episode, the recurring argument is that French (and Swedish) police pushed past their own countries' strict DNA privacy laws to solve cases they viewed as otherwise unsolvable, betting that the moral and practical necessity of catching violent offenders outweighed uncertain legality. That tension resurfaces at the end unresolved: even after the technique cracked the Predator of the Woods case, France's constitutional court blocked formal authorization of the method, leaving victims of other cold cases pressing for its use while the legal framework across Europe remains contested.

What was discussed

Predator of the Woods cold case origins0:15

Beginning in 1998 in La Rochelle, an attacker later dubbed the Predator of the Woods abducted and raped a 16-year-old girl, and is believed to have raped at least four more young women and teenagers through 2008. Police collected matching DNA from each crime scene but had no suspect, and France's limited law-enforcement DNA database, which only held profiles from people previously arrested for serious crimes, produced no match.

Rise of US recreational DNA testing3:09

Tens of millions of Americans voluntarily submitted DNA to companies like 23andMe and Ancestry.com to explore genetic heritage and family trees. Law enforcement realized these massive databases could be repurposed to trace distant relatives of unknown crime-scene DNA, giving rise to genetic genealogy as an investigative technique.

Golden State Killer solved via genealogy4:47

News clipclip
Announces the arrest of the man identified as the Golden State Killer after decades on the run
Matthew Daltonassertion
Genetic genealogy by tracing distant relatives is a revolutionary technique that can crack decades-old unidentified-DNA cases

Europe's stricter DNA privacy laws7:31

Unlike the US, recreational DNA testing is illegal in France without a court order through an accredited lab, and DNA data is treated as almost sacrosanct under European law, with databases barred from selling or sharing it. Matt attributes this to a broader European expectation of privacy compared with Americans, though he notes concerns that such data could still be misused, for example by insurers profiling genetic risk.

French police turn to FBI despite legal risk13:13

Matthew Daltonassertion
Relying on a foreign database not authorized under French law created real uncertainty about whether a resulting case could hold up in court
victim's lawyer (quoted by Matt)opinion
Society will not accept that a technology to solve the crime exists but investigators refuse to use it

Sweden's earlier use of the technique14:07

Swedish police had already used overseas commercial DNA databases and genetic genealogy once before, in 2020, to solve a 16-year-old double murder despite a domestic ban on police accessing such databases. Afterward, Sweden's Data Privacy Authority halted the practice for years until the legislature created a legal framework last year restricting its use to the most serious crimes when other avenues are exhausted.

FBI genealogy match narrows to three suspects15:22

The FBI matched the Predator of the Woods' DNA to a distant relative, Mathieu Bouvet, a professional archivist who had built and posted an online family tree of roughly 6,000 people. Months later the FBI found a second distant match in eastern France and then identified the ancestral couple, born in 1901 and 1902, where the two family trees intersected, allowing French police to narrow hundreds of descendants down to three men matching the suspect's age and physical profile.

Arrest, confession, and suicide of the suspect18:32

French police identified Bruno Lambrich-Gonzalvo, a 62-year-old local election candidate with an expunged 1980s sexual assault conviction, as the most probable suspect, raided his home, and confirmed the match via a new DNA sample. He told a judge he had wondered when he would be caught, but before trial he died by suicide in his prison cell in March 2024.

French law struck down, victims push for the technique20:30

French lawmakers passed a measure this year to formally authorize the FBI-style genealogy technique for the most serious crimes, similar to Sweden's law, but France's constitutional court struck it down for not sufficiently protecting DNA privacy. Meanwhile victims of other unsolved crimes, such as the case known as the violeur d'Antibes, have organized to demand the technique be used, arguing the French justice system is taking too long, even as Germany and the UK also restrict police DNA-database access and London's Metropolitan Police runs its own pilot program.