Searches Of Consumer DNA Databases By Law Enforcement Limited In Two US States


Tom Hale


Tom Hale

Senior Journalist

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist


While the benefits of commercial genealogical databases are clear, the growing use of genetic data has been seen as an emerging threat to individuals’ privacy and civil liberties. Image credit: Sergei Drozd/

The use of consumer genealogical websites to catch killers, like the method used in the 2018 arrest of the "Golden State Killer", has been tightened up under new laws in two US states. 

Both Maryland and Montana have made it tougher for the forensic genealogical methods to be used in criminal cases in order to safeguard peoples’ genetic privacy. It’ll still be possible for investigators to use this novel and invaluable method, but only if it’s given the thumbs up from legal authorities. 


In Maryland, the new law dictates that a court must first approve the use of certain forensic genetic genealogical DNA analyses and searches. It also prohibits investigators from obtaining certain information on people, such as their medical history, and requires judicial authorization before biological samples are covertly collected for use in genealogical profiling. 

The new legislation in Montana requires investigators to obtain a search warrant before they can use a commercial DNA database to identify suspects.

The past decade has seen the rise of commercial genealogical and ancestry websites, used by people trying to find distant relatives and trace their family tree. However, many people are unaware that some (not all) of these platforms share customers’ genetic data with third parties, from the pharmaceutical industry and scientists to law enforcement. 

23andMe, Helix, and Ancestry have kept their genetic databases closed to law enforcement without a warrant. However, GEDmatch and FamilyTreeDNA have previously shared their database with investigators – sometimes with some remarkable success.


In 2018, the serial killer and rapist Joseph James DeAngelo, better known as the “Golden State Killer,” was arrested with the help of genetic insights from the commercial genealogy website GEDmatch. DeAngelo had committed at least 13 murders, 50 rapes, and 120 burglaries across California between 1973 and 1986.

Police compared genetic material left at the crime scene to the DNA of people who voluntarily submitted their gene information to public genealogy databases to trace their own family tree. This was able to identify a number of DeAngelo’s family members, eventually leading them to DeAngelo himself. After following the suspect, they then picked up an object he discarded to obtain his DNA, which then linked him to a number of the crimes. DeAngelo was sentenced to life imprisonment in August 2020 without the possibility of parole.

In 2020, similar techniques were also used to identify and arrest Daniel Nyqvist, a murderer who stabbed a child and woman in the Swedish city of Linköping in 2004. 

While the benefits of commercial genealogical databases are clear, the growing use of genetic data has been seen as an emerging threat to individuals’ privacy and civil liberties. The lawmakers in Maryland said they hope their new legalization hopes to maintain individuals’ rights, while not making it unnecessarily difficult for investigators to catch a killer. 


“This bill strikes a balance between this very important technology to identify people that do the very worst things to our Marylanders, yet it balances that against the privacy concerns and the trust that we need from the public in this type of science,” John Fitzgerald, the chief of the Chevy Chase Village Police Department, testified to the Maryland Judiciary Committee on February 23, 2021.

“It does these things to put guardrails on a very important science.”



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  • golden state killer