On the night of May 31, 1921, a white mob descended on the affluent Black neighborhood of Greenwood in Tulsa, Oklahoma. The mob had gathered after the arrest of a Black teenager named Dick Rowland, who had been falsely accused of assaulting a white girl in an elevator. In one of the worst episodes of racial violence in US history, thousands of white vigilantes took to the streets of Greenwood with torches, guns, and bombs. In a matter of hours, the rioters destroyed more than a thousand homes and hundreds of businesses across 35 blocks of the Greenwood district—so prosperous it was called “Black Wall Street. ” Historians estimate that dozens to as many as 300 Black people were killed during the massacre. Some are believed to have been buried in unmarked graves. In 2020, the city of Tulsa finally began excavations to search for those graves. So far, archaeologists have exhumed 19 sets of human remains at a local cemetery that may be linked to the massacre. Now, scientists working for the city have obtained enough usable DNA from two individuals to potentially learn their identities. The researchers say genetic material from these two people’s living descendants could help identify the nameless victims. “These people deserve their names. They deserve to be identified. Their families deserve to know who they are,” says Danny Hellwig, director of laboratory development for Intermountain Forensics, a nonprofit laboratory based in Utah hired by Tulsa officials to do the DNA analysis. But some residents and privacy experts worry that this genetic data could be used for purposes beyond the identification project, including in criminal investigations, because people are being asked to upload their data to a genealogy website used by law enforcement . “You can’t underestimate the dangers,” says Eric Miller, a professor at Loyola Law School in Los Angeles who is of mixed race Scots-Caribbean heritage. Miller is an attorney for Justice for Greenwood, a Tulsa-based nonprofit that is seeking reparations for the survivors and descendants of the massacre. The group isn’t directly involved in the identification project but recently hosted an online town hall to discuss their privacy concerns. “The only people being asked to donate their DNA are the descendants of the Tulsa Race Massacre. It was a race massacre. Therefore, the descendants are all Black,” says Miller. People with connections to the massacre can take a DNA test through 23andMe, Ancestry, FamilyTreeDNA, or MyHeritage. (Free test kits are available to those who want to participate, but about 70 percent of the people who have inquired about the project have already taken a consumer DNA test at some time in the past. ) They then upload their raw genetic data file to GEDmatch , a free genealogy website that’s open to the public. Using that data file, the site generates relative matches based on the amount of DNA users share with other people in the database. For this to work, of course, a person—in this case, someone who died in the 1921 massacre—must be in the database in the first place. Intermountain Forensics is creating DNA profiles from the two sets of remains, which will be uploaded to the site. If researchers find modern-day matches to those individuals, they’ll map out their family trees with the goal of uncovering their identities. Hellwig says more than 50 presumed descendants are participating in the project so far. The technique is known as genetic genealogy, which was most famously used to identify Joseph James DeAngelo as the Golden State Killer in 2018. It was quickly adopted by police departments across the US and has since been used to solve hundreds of homicide and sexual assault cases in the country. It can be controversial, though, such as when blood taken during a newborn health screening was used to implicate the child’s father in a crime . But this is far from the first time family members’ genetic material has been used to put names to unidentified remains. Scientists around the world have used DNA to identify missing persons and victims of war, genocide, and natural disasters. The International Commission on Missing Persons, or ICMP, a nongovernmental organization based in The Netherlands, has conducted several DNA profiling efforts, including in the Western Balkans, to identify Muslim men and boys killed in the 1995 Srebrenica genocide during the Bosnian War. In these cases, scientists typically invite close family members of the missing to provide blood samples; then they create DNA profiles from the samples, to be compared to those obtained from remains. The organization’s testing method focuses on a type of DNA variation called short tandem repeats, or STRs. By contrast, consumer tests analyze people’s genetic code by looking at single nucleotide polymorphisms, or SNPs, single-letter changes in DNA sequences that make people unique. STRs are useful in determining closer relationships, whereas SNPs are more stable genetic markers that can be used to establish more distant relationships. There’s another important distinction between the two approaches, says Kieren Hill, DNA laboratory manager for ICMP: “The difference with what we do is that our data is stored on our own servers. ” The organization’s database is private and cannot be accessed by law enforcement. By contrast, GEDmatch is an online piece of software that can be used by anyone, including law enforcement agencies investigating certain violent crimes. That’s the reason for Miller’s privacy concerns. Miller says adding more Black profiles to the database will create more opportunities for law enforcement to investigate Black people—for example, if police use the GEDmatch profiles to connect the relatives to DNA found at modern crime scenes. “It’s not just yourself that you’re putting at risk. It’s your parents, your cousins, your children, your unborn descendants, your whole family tree,” he says. Even for people who have never committed a crime, there are risks to uploading genetic data to a public website. Crime scene DNA samples are not necessarily from perpetrators—they could be left by innocent bystanders. Or a person may be a sufficiently close match to get swept into an investigation, even if they are actually only a relative of the person who was involved. But GEDmatch has its benefits. It contains the profiles of more than 1. 3 million people, whereas ICMP has collected around 120,000. The more profiles available, the higher the likelihood that researchers will be able to identify the Tulsa victims. “It’s the most powerful tool available,” says Hellwig. It’s also more likely to match distant relatives. The Tulsa massacre happened a century ago, and the victims’ descendants may now be living anywhere. The GEDmatch database is international, and it relies on SNP matching, which works for these looser connections. The ICMP, by contrast, works on more recent events in specific geographic areas; in many cases, there are living family members who can provide samples. For the STR testing the group uses, three reference samples are typically needed from a parent, child, or sibling of a missing person to make a match. With few first-degree relatives of Tulsa victims still alive, that kind of matching isn’t possible. In a statement to WIRED, Carson Colvin, a spokesperson for the city of Tulsa, called GEDmatch the “best option available for connecting the undocumented remains buried at Oaklawn Cemetery with their living family members. ” Colvin points out that GEDmatch has different levels of privacy settings , including one that allows users to opt out of law enforcement searches. Users can also change these permissions whenever they choose, or delete their profiles altogether. City officials may eventually be informed of the names of relatives that closely match with the unknown bodies, but they won’t have access to individuals’ DNA samples or their raw data files. GEDmatch also does not hold raw data files, according to Brett Williams, CEO of Verogen, the forensics company that owns the database. “All data in GEDmatch is encoded upon upload, and the initial raw data is subsequently deleted,” he says. Still, it’s understandable that Black people might be hesitant to contribute their DNA to the project, says Keisha Ray, a bioethicist and assistant professor at the McGovern Center for Humanities & Ethics at UT Health Austin, who is not involved in the Tulsa project. “Concern about data collection is always heightened whenever it’s with racialized minorities or people of color,” she says. “It all requires a lot of trust on Black people’s part. And that trust has been taken advantage of in the past. ” Hellwig says his lab is working with community members who have inquired about uploading to GEDmatch to ensure they are aware of the different privacy settings. “I don’t begrudge anyone for having privacy concerns,” he says. “We see this as an individual choice. You choose the level of searchability you have within that database. ” Those who don’t feel comfortable uploading to GEDmatch can send their raw DNA file from any of the four testing companies directly to Intermountain Forensics, where it will undergo a one-to-one comparison with the DNA profiles of the unidentified remains. Miller and the members of Justice for Greenwood want to make sure that the Tulsa descendants understand these options and don’t settle for default settings. Miller is also concerned about how long people’s profiles would need to stay on GEDmatch, considering there are potentially many more remains to be tested. He says it would have been better to ask descendants to contribute DNA once all the burial sites had been unearthed. After all, one big question mark lingering over the whole project is whether the remains that have been discovered so far are actually those of massacre victims. Even if they’re not, Hellwig says, genetic genealogy could help solve the mystery of who those people were. “No matter what, they deserve to have their names,” he says. .