For more than a year, investigative genealogy opened the doors to a law enforcement crime-solving spree, cracking decades-old murder and rape cases that once seemed impossible to solve.

At press conferences around the country, police announced arrests using leads generated from a DNA database called GEDmatch, a free, public website. Once a place for amateur sleuths looking for long-lost relatives, police discovered the database could also be used to lead them to elusive killers.

“This is the new frontier,” heralded Todd Spitzer, the Orange County, California, district attorney, whose office is currently prosecuting four genealogy cases and reviewing several more. “It’s provided incredible enhancements to the tools available to law enforcement.”

Nearly 70 people suspected of murder or rape have been identified across the country using the revolutionary investigative technique, but law enforcement’s use of public DNA databases also quickly raised privacy concerns. Following a public backlash, GEDmatch in May changed its terms of service forcing users to “opt-in” to have their profiles available for law enforcement searches.

What was once seen as a nearly endless well of leads for law enforcement, suddenly came to a near-complete halt.

Law enforcement officials and genealogists told BuzzFeed News the changes to GEDmatch, one of the few public DNA databases used by law enforcement, have significantly reduced the number of cases solved since May. While authorities have recently announced breaks in cases, the DNA profiles used to match relatives of suspects in many of those cases had been uploaded into the database before the changes were made.

“There are going to be cases that could have been solved that haven’t been solved,” Robert Mestman, head of Orange County’s science and technology unit told BuzzFeed News. “It’s probably going to slow things down.”

Worries about law enforcement agencies accessing DNA databases used by the public were sparked almost immediately after authorities announced in April 2018 the arrest of the suspected Golden State Killer for the murder of 12 people in California, using genetic genealogy. Yet the prospect of catching violent criminals and solving well-known cold cases promised that arrests using the new technique would garner headlines across the country.

Direct-to-consumer DNA testing companies, including 23andMe and Ancestry, tried to assuage worries by pointing to their terms of service and prohibiting law enforcement from using their services or databases.

In January, that FamilyTreeDNA, one of the biggest consumer DNA testing companies, had quietly begun to work with the FBI, giving agents the ability to search its database of more than a million profiles for a possible familial match to suspects.

Then in May, the retired businessman who operates GEDmatch, Curtis Rogers, gave Utah police permission to use the database to solve the violent assault of a 71-year-old woman inside a Mormon church. The decision, at the time, helped identify a 17-year-old suspect, but also went against the terms of use delineated by the website.

GEDmatch had previously allowed law enforcement to its its database only to solve murders and sexual assaults but, at the request of police in Utah, Rogers had agreed to make an exception, sparking criticism that the site was not abiding by its own rules to protect its users’ privacy.

The decision prompted worries among genealogists of a “slippery slope” by allowing law enforcement to investigate less serious crimes. It also rehashed several of the same worries genealogists had when FamilyTreeDNA began quietly working with the FBI.

After an outcry, GEDmatch revamped its privacy policy and automatically restricted its more than 1.2 million DNA profiles from law enforcement searches. If a user wanted to make their genetic information available, they would have to intentionally opt-in.

“Genetic genealogists who are working cases, they are so disappointed,” said Diahan Southard, founder of Your DNA Guide, which helps people decipher and investigate the results of their DNA tests.

For law enforcement, the decision had an immediate effect.

“We’re still working cases that have data from before the opt-out,” Lori Napolitano, chief of forensic services at the Florida Department of Law Enforcement (FDLE) told BuzzFeed News. “But comparing what we would see in terms of matches before, to what we see in those cases now, it’s pretty drastic.”

While most law enforcement agencies have contracted laboratory testing and genealogical work to third parties, Florida is one of a handful of jurisdictions to create its own investigative genealogy unit. In the past year, the agency has helped law enforcement across the state use investigative genealogy to crack four cases, including a man suspected of killing at least three women.

The agency has about 20 cases pending before it, but since GEDmatch changed its rules of access to law enforcement, the agency hasn’t cracked a single case.

“We have not had a case come back,” since the policy change in May, Napolitano said.

Over the past five months, GEDmatch users have slowly started to opt in to law enforcement searches, those familiar with it said, creating an estimated pool about 15% of its original size, or about 180,000 DNA profiles. That figure continues to swell by about 30,000 profiles a month, and law enforcement officials and the genealogists who work with them are patiently waiting as it repopulates.

“It just takes more time,” Colleen Fitzpatrick, co-executive director of the DNA Doe Project, which uses investigative genealogy to identify unknown victims, told BuzzFeed News. “You work with what you have.”

Since May, the DNA Doe Project has identified a handful of victims, but the changes to GEDmatch’s service has made it significantly more difficult.

“The opt-out change set us back a lot,” Margaret Press, who co-founded the organization, said. “It’s slowing people down, but it’s not stopping us.”

Press said the organization has identified five victims in recent months, two of them through the use of another database with FamilyTreeDNA.

“Skill and luck have helped compensate a bit,” she said.

But after seeing the potential of investigative genealogy, police across the country are not giving up.

Law enforcement agencies and the DNA databases they use have launched a public outreach campaign to encourage the public to upload genetic information to the databases and opt-in for law enforcement searches in order to become “genetic witnesses.”

While FamilyTreeDNA apologized to its customers for not notifying them sooner about the company’s work with law enforcement, the firm has since embraced its new role. It now advertises its services as a way for customers to not just learn about their lineage, but to help law enforcement catch suspected killers.

In Florida, Napolitano recently held a press conference hoping to teach Floridians about the benefits of investigative genealogy, and to press the public to upload their data to the databases.

In California, some law enforcement agencies are also getting directly involved.

The Institute for DNA Justice, a non-profit aiming to “educate the public about the value of investigative genetic genealogy as a revolutionary new tool to identify, arrest, and convict violent criminals” was recently registered in California with the goal of raising $2 million for the outreach effort.

The organization, which encourages users to upload DNA data to both GEDmatch and FamilyTreeDNA, is headed by Sacramento District Attorney Anne Marie Schubert, Ventura County District Attorney Gregory Totten, and Jill Spriggs, Bureau Chief at the California Department of Justice, according to her LinkedIn profile.

Law enforcement agencies, genealogists, and direct-to-consumer DNA testing companies have also met in an effort to address the privacy concerns that have emerged from investigative genealogy.

During a four day conference this week, some of the most prominent figures that helped propel the use of investigative genealogy met at the Cold Spring Harbor Laboratory on New York’s Long Island.

Titled, “Emerging Issues of Privacy, Trust, And Societal Benefit from Consumer Genomics,” attendees included representatives from the FBI, Gene by Gene (the parent company of FamilyTreeDNA), Parabon NanoLabs, GEDmatch, Identifiers International and the ACLU.

“Genealogists and law enforcement have never been very comfortable with each other,” Fitzpatrick said. “Now there is a compelling reason why these groups have to work with each other.”

Fitzpatrick declined to offer details on the meeting. The FBI declined to comment.

Despite the hurdles, law enforcement agencies that have invested resources in the emerging field remain hopeful.

In Orange County, California, the district attorney’s office is looking to hire its own genealogist and has built the foundation of its investigative genealogy unit to assist the 30 law enforcement agencies in the county.

But if the changes to public DNA databases prove anything, it’s that the new field can still be drastically disrupted by policy changes, public opinion, or lawmakers who could decide to step in to address concerns.

“If we get too cute with techniques, if we use techniques that are not traditional law enforcement techniques, then the policymakers, Congress, and state legislators, they’re going to come in and dictate what we can and can’t do,” Spitzer said. “We don’t want to lose this as a tool because it’s seen as if it’s being abused.”