Investigative genetic genealogy can help police identify an unknown person through distant relatives’ DNA. Here is how the process works, where its limits lie, and what to consider before sharing your family’s genetic information.
A DNA test taken to explore family history may seem far removed from a criminal investigation. Yet a person who uploads genetic data to a searchable genealogy database may appear as a relative of an unknown DNA sample. Investigators can use that connection, alongside family records, to develop a lead—even if the person they are trying to identify has never taken a consumer DNA test.
That possibility has helped resolve difficult cases. It also raises a question for anyone documenting a family’s past: how do you preserve and explore family history while making deliberate choices about genetic privacy? Understanding what police can search—and what a DNA match does not establish—is a useful place to start.
Investigative genetic genealogy combines DNA analysis with conventional family-history research. Its purpose is to suggest an identity for an unknown DNA sample, often from crime-scene evidence or unidentified human remains. A genetic match points investigators toward possible relatives; records and further investigation help them work out who the unknown person might be. The match itself is a lead, not a finding of guilt or a final identification.
In a conventional U.S. criminal investigation, a laboratory may create a short tandem repeat, or STR, profile from evidence and search it in CODIS, the law-enforcement DNA system. Investigative genetic genealogy uses a different kind of profile based on many single-nucleotide polymorphisms, or SNPs. The larger set of markers can reveal connections to more distant relatives in participating genealogy databases. A CODIS profile is not simply uploaded as-is to a consumer genealogy site; the two approaches use different profiles and serve different investigative purposes.
If a suitable forensic sample can be developed into a SNP profile, investigators search it through a genealogy service that permits the relevant law-enforcement use. The service may return potential relatives and an estimate of how much DNA they share with the unknown person. Genealogists then examine records—such as birth, marriage, death, and census records—to build and compare family branches. They look for a person who fits both the genetic relationships and other known details of the case.
Imagine that an unknown sample has matches to two distant cousins from different branches of an extended family. Researchers may trace those branches toward shared ancestors, then work forward through descendants. Dates, locations, and other evidence can narrow the possibilities. This is painstaking research, not a database revealing a suspect’s name at the press of a button. A distant cousin whose profile appears in the results is a potential source of family-tree information, not a suspect by virtue of the match.
The 2018 Golden State Killer investigation made this method widely known. Investigators used GEDmatch to find genetic connections to distant relatives, researched family lines, and identified Joseph James DeAngelo as a suspect. They then compared DNA obtained during the investigation with the crime-scene evidence. The genealogy search helped point the investigation in a direction; it was not the sole basis for the identification.
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Preserve our memoriesThat distinction matters in every case. A family tree can contain errors or missing relationships, and a forensic sample may be too limited, degraded, or mixed to support the work. The U.S. Department of Justice’s interim policy says a person must not be arrested solely because of an association produced by a genealogy service. When an investigation identifies a suspect under that policy, a direct STR comparison with the forensic profile is required to confirm that the sample could have come from that person.
“Family DNA database” is a broad description, not a single set of access rules. Consumer testing services, sites that accept uploaded DNA files, and law-enforcement systems have different policies. Whether a profile is included in a particular search depends on the service, the purpose of the search, the user’s settings, and applicable legal requirements. Terms and settings deserve a fresh look before uploading a file or changing its visibility.
GEDmatch, for example, distinguishes between searching to identify unidentified human remains and searching for perpetrators of violent crimes. Under its Public + Opt-Out setting, a kit can be compared with kits used to identify remains but not with law-enforcement kits seeking perpetrators of violent crimes. The Public + Opt-In setting, by contrast, includes comparisons for violent crimes. GEDmatch says investigators using its service do not receive a matching user’s raw DNA data; they can see specified match information, including a name or alias, email address, and amount of shared DNA.
FamilyTreeDNA offers Investigative Genetic Genealogy Matching as a separate voluntary choice. Its stated matching conditions include opting in to ordinary matching and to investigative matching. A participating investigative account that has a DNA match can see information made accessible to matches under the service’s rules. Checking those settings is more reliable than assuming that taking a DNA test automatically makes a profile searchable—or automatically excludes it.
Other major services take a different approach. Ancestry says it does not allow law enforcement to use its services to investigate crimes or identify human remains and does not voluntarily provide data to law enforcement; it also says agencies may seek information through valid legal process. 23andMe says criminal casework falls outside its service’s intended use and that it resists law-enforcement requests, while acknowledging circumstances in which it may have to respond to valid legal process. These policies are not a blanket guarantee that genetic information can never be disclosed.
The U.S. Department of Justice’s interim policy applies to investigations within its stated scope, including certain DOJ investigations and federally funded work. It generally requires investigators to search an eligible forensic profile in CODIS without a confirmed, probative match and pursue reasonable leads before using forensic genetic genealogy. It also calls for consultation with a laboratory official and a prosecutor. Its case criteria focus on specified serious offenses and suspected homicide victims’ remains, with a defined route for certain other threats. It should not be mistaken for one rule governing every police agency or every country.
The DOJ policy also requires agencies to identify themselves to genealogy services and to use services that give explicit notice of the relevant law-enforcement use. It restricts use of forensic profiles to identification purposes and prohibits using them to determine medical conditions or psychological traits. These safeguards are important, but privacy concerns do not end with the rules for a single investigation: a search may still involve people who did not upload DNA or agree to appear in an investigative family tree.
Your DNA is personal, but genetic relationships are shared. If you upload a profile, a match may help identify relatives who have never used that database. Conversely, your own absence from a site does not mean a distant relative’s profile could never point investigators toward your branch of a family tree. That is why consent is more complicated here than deciding what to do with an ordinary photograph or document.
The issue is not simply whether using the technique is good or bad. Families seeking answers about an unidentified loved one may see considerable value in it; others may have serious concerns about the reach of a search, the involvement of relatives who did not consent, or unexpected discoveries about parentage. Researchers have identified the privacy of nonparticipating relatives as a particular concern in investigative genetic genealogy.
A careful approach does not require abandoning genealogy. It means separating several decisions that are often treated as one:
These steps cannot make genetic privacy absolute. They do make your choices more informed. A family can also preserve a great deal without a DNA test: interview relatives, identify people in old photographs, record where a recipe came from, and note how people are connected. That context may answer the questions future generations care about most, without treating a genetic profile as the whole family story.
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Create a family legacyA DNA match can suggest a biological connection; it cannot explain what a person was like, why a tradition mattered, or who became family through adoption, partnership, friendship, or care. For those stories, families need more than test results. They need a place to preserve names and relationships alongside memories and the context that gives them meaning.
MyHeirloom’s Family Tree can represent genetic and non-genetic relationships, while My Tribe provides space for important people beyond a narrow ancestry chart. A grandparent’s story might begin with a family-tree connection, then gain depth through a Keepsake containing their voice, a photograph with names and dates, or a note about the person who taught them a family ritual. In a Legacy Room, those pieces can sit within a more coherent life story instead of remaining scattered across phones, social posts, and folders.
That distinction is especially useful after a surprising DNA discovery. A family might want to document a newly understood relationship while giving the people involved time and choice over what is shared. MyHeirloom’s user-controlled visibility can help keep a personal story private or share selected content where appropriate. For sensitive records and instructions, DocuVault provides a separate space; it should not be confused with a genetic testing service or presented as a place to submit DNA for matching.
Start for free with MyHeirloom if you want to build that context gradually. One labeled photo, a short account of a relative’s life, or a carefully recorded family connection is enough to begin. Weaver can help prompt reflection when you know a memory matters but are unsure how to describe it. MyHeirloom helps turn scattered memories, relationships, and important information into an organized, secure, meaningful legacy for future generations—without reducing that legacy to a DNA result.
Investigative genetic genealogy uses DNA matches to generate leads, then relies on family-history research and further investigation to test them. It has helped investigators find answers, but it also affects relatives who may never have chosen to join a database. The most useful response is to understand a service’s rules, make deliberate sharing choices, and remember that a genetic connection is only one part of family history.
Preserving the rest can start with something small and concrete: a name behind a photograph, a story in someone’s own words, or the relationships that made a household a family. Start for free with MyHeirloom to give those memories a place alongside your family connections, with the context future generations will need to understand them.
1. Can police search every DNA testing company’s database?
No. Services have different policies and access arrangements. GEDmatch and FamilyTreeDNA describe forms of permitted investigative matching, while Ancestry says it does not permit police to use its service to investigate crimes; valid legal process is a separate question. Check the current policy of the specific service you use.
2. Does a relative’s DNA match mean someone in the family is a suspect?
No. A match indicates a possible genetic relationship to an unknown sample. Investigators must research the relationship and assess other evidence; under DOJ policy, a person cannot be arrested solely because of a genealogy-service association.
3. Is investigative genetic genealogy the same as a CODIS search?
No. CODIS generally searches forensic STR profiles, while investigative genetic genealogy uses SNP-based profiles to look for relatives in eligible genealogy databases. The approaches can be used at different stages of an investigation.
4. If I opt out of law-enforcement matching, can my DNA never be involved?
Do not assume that. Settings can distinguish between types of searches: GEDmatch’s Public + Opt-Out category, for example, excludes comparisons for violent-crime perpetrators but includes comparisons involving unidentified remains. A relative’s separately shared DNA may also lead researchers toward your family branch.
5. Can MyHeirloom analyze DNA or search police databases?
No. MyHeirloom is a platform for preserving stories, relationships, media, recipes, and important information—not a DNA testing or investigative matching service. Its value here is helping you document the people and context behind a family tree while making thoughtful choices about what you share.
MyHeirloom gives you a dedicated Legacy Room—a private, secure space to collect photos, videos, documents, and stories.
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