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Forensic genealogy is the newest member of the forensic family—and its ability to match people to evidence could be as revolutionary to investigations as the use of fingerprint analysis was.
Since cracking its first case in 2018, forensic genealogy has helped identify suspects in over 1,000 cases of murder, sexual assault, and unidentified remains by early 2026. Labs now solve dozens yearly, with hundreds more cleared since the Golden State Killer. But regulators, citizens, and genealogists worry about privacy risks and court rules.
Forensic genealogists use genetic information to match individuals to DNA samples. This often means utilizing open-source databases, such as GEDMatch. While GEDMatch does not offer genetic testing itself, it does allow the upload and comparison of DNA data from third parties, including direct-to-consumer services such as Ancestry.com or 23andMe. GEDMatch holds the genetic profiles of over 1.2 million individuals, which is enough to identify a third cousin (or closer) of a DNA sample in 90 percent of the US population. Law enforcement can then use this capability to begin building a family tree of a suspect and/or victim, aided by public records and traditional sleuthing.
Case Example: Catching the Golden State Killer
The first person that forensic genealogy put behind bars was a former police officer named Joseph James DeAngelo. As the Golden State Killer, he terrorized Californians off and on from 1973 to 1986: 13 murders, 50 rapes, and 120 burglaries. His identity eluded law enforcement for decades.
In 2018, investigators pulled the Golden State Killer’s DNA from a rape kit and uploaded it to GEDMatch. In return, they received over a dozen people who had the same great-great-great-grandparents as the killer. Working with a genealogist, the investigators began constructing a large family tree, ultimately narrowing their search to two possible suspects. When a follow-up DNA test ruled out one of those two, the investigators had their prime suspect: Joseph James DeAngelo.
After collecting a sample of DeAngelo’s DNA from his car door handle and another from a tissue he discarded, the team of investigators and genealogists ran further tests and found that these samples matched DNA collected from the crime scenes of the Golden State Killer. DeAngelo was arrested on April 24, 2018, and was eventually sentenced to multiple consecutive life sentences, with no possibility of parole.
The Controversy Surrounding Forensic Genealogy
Forensic genealogy is the most powerful tool that investigators have gained in the 21st century, but its quick adoption and lack of oversight have led to some serious debates around privacy and due process.
Most forensic genealogy investigations are performed without a warrant, yet they search through millions of people’s records to access extremely sensitive personal health information about an individual—information that has not been explicitly volunteered. Websites and tools that were originally meant to help people discover their ancestry are now being utilized by investigators in a way that may violate a citizen’s Fourth Amendment rights.
After the Golden State Killer arrest, law enforcement’s interest in these databases surged. FamilyTreeDNA, for example, quietly allowed the FBI to use its database for investigations before publicly updating its privacy policy and telling customers what was happening. Major companies like Ancestry and 23andMe say they will only work with law enforcement when they receive a valid legal request, such as a court order or search warrant.
GEDmatch, the site most closely associated with forensic genealogy, changed its rules in 2019. Users now must actively opt in if they want their DNA data to be available to law enforcement searches. Only a minority of users have chosen to do this, which sharply reduced how much of the database investigators can see compared with the early days of forensic genealogy. In 2019, GEDmatch was bought by Verogen, a forensic DNA company that was later acquired by QIAGEN, signaling a stronger focus on law enforcement work.
Concerns are not just about privacy. Forensic genealogy has helped solve many cold cases, but it has also pointed to innocent people when matches were weak or when segments of DNA were misread. Direct-to-consumer test results can contain errors, and small shared DNA segments are easy to misinterpret, which can send detectives down the wrong path. Because of these risks, several U.S. states now require a warrant or strict conditions before police can use forensic genealogy databases.
The Future of Forensic Genealogy
In September 2019, the U.S. Department of Justice issued the first federal guidance on forensic genealogy. Federal investigators can use it only for murders, rapes, or identifying human remains—and only after other methods fail. They also need warrants for secret DNA collection and approval from a prosecutor. The rules don’t apply to state or local police, who handle most investigations.
States have gone their own way. As of 2026, around nine states require warrants or court orders for police to use consumer DNA databases. Utah has introduced a bill that would ban law enforcement genetic searches, while New York has proposed a policy that would allow them. Washington state has split the difference and suggested that they should only be an option when requested through valid legal processes. This patchwork of conflicting guidance may not amount to much more than confusion in a world where cases and families often cross state lines.
A 2019 survey by the Pew Research Center found that 48 percent of Americans thought it acceptable for DNA testing companies to share customers’ genetic data with law enforcement. But with up to 90 percent of the country potentially identifiable through forensic genealogy, that’s a lot of Americans being searched without consent.
A 2020 American Journal of Human Genetics survey of over 36,000 people worldwide found that less than half were willing to share DNA even for medical research, because of low trust in how it’s handled. Forensic genealogy needs clear government rules, careful investigations, and company oversight to build back that trust.
Forensic genealogy has done a lot in a short time, but its rapid growth has shown some problems. The promise of solving cold cases may be too strong to stop. But as the field adds formal training—like the University of New Haven’s forensic investigative genetic genealogy graduate certificate—plus certification and research, it can match the standards of other forensic fields.
Matt Zbrog
WriterMatt Zbrog is a writer and researcher from Southern California. Since 2018, he’s written extensively about the increasing digitization of investigations, the growing importance of forensic science, and emerging areas of investigative practice like open source intelligence (OSINT) and blockchain forensics. His writing and research are focused on learning from those who know the subject best, including leaders and subject matter specialists from the Association of Certified Fraud Examiners (ACFE) and the American Academy of Forensic Science (AAFS). As part of the Big Employers in Forensics series, Matt has conducted detailed interviews with forensic experts at the ATF, DEA, FBI, and NCIS.