VALDOSTA, Ga. — On an October morning in 2018, Eleanor Holmes and her husband left home to run an errand and found two men inside their front gate. They introduced themselves as detectives from Orlando, Florida, and said they needed the couple’s help.

Standing in the driveway, the casually dressed detectives said they were trying to identify someone who’d been found dead many years earlier, the Holmeses recalled. They were looking for the person’s relatives, and were using DNA and genealogical records to stitch together a family tree that they hoped would lead them to a name. Friendly and businesslike, they said they’d already got DNA samples from Eleanor Holmes’ sister and an aunt. And now they wanted hers.

Holmes already knew about the detectives’ visit to her sister. It worried her that someone in her family had died without anyone knowing about it. She had relatives in Orlando, including a niece whom she hadn’t heard from in more than a decade. So she agreed.

“I just did it because that was the only thing on my mind, my niece. That was it, bottom line,” Holmes said in a recent interview.

The detectives, still standing in the driveway, swabbed Holmes’ cheek and put the sample in a container. They thanked her, gave her a business card and drove away.

She thought nothing of it until a few days later, when she got a frantic phone call from the girlfriend of one of her sons, Benjamin Holmes Jr. Orlando police had just arrested him for allegedly fatally shooting a college student, Christine Franke, in her Florida home in 2001. They’d used DNA and genealogical records to tie him to the crime.

In that panicked moment, it dawned on Holmes that the detectives hadn’t told her the truth. They’d used her DNA to help build a case against her son.

“When they arrested him, I knew they were lying,” Holmes said. “They lied to us.”

Police have said that the arrest of Benjamin Holmes Jr., 39, shows their commitment “to do everything we can to solve crimes.” Franke’s family says the arrest has given them long-needed answers about her death and allowed them to stop wondering if the killer was still out there, free to prey on others.

Benjamin Holmes Jr. and his parents, though, say he is innocent. He has pleaded not guilty, and his trial, scheduled for June, may be the first to explore how police conduct investigations using genetic genealogy, a largely unregulated technology that has exploded in popularity in recent years.

Holmes and her husband, who are both in their mid-70s, aren’t the only ones in their family who feel misled by police. In the months before taking her DNA, Orlando detectives visited more than a dozen of her relatives in Florida and Georgia. Several said they were told a similar story before agreeing to provide DNA samples.

“It was just deception, not only to me but all my other family members, because they know what they were looking for when they took the DNA,” Holmes said. “They weren’t looking for someone in our family that had been killed, or that was dead. They were looking totally to find out whether or not our DNA coincided with Benjamin’s. That’s what they were looking for.”

For 17 years, Orlando police detectives had tried to figure out who killed Franke. Although the case had gone cold, each did what they could with the available technology and manpower. But every lead, every potential clue found at the scene, left them, and Franke’s family, without answers.

“I thought they’d never catch him,” Franke’s mother, Tina, 70, said.

Franke, 25, was one of four siblings raised in Vero Beach, outside Orlando. An aspiring elementary school teacher, she was studying at the University of Central Florida while working as a server at a restaurant near the Universal Orlando theme parks. She lived with her girlfriend about a half hour away, on the north side of town.

Early in the morning of Oct. 21, 2001, after working a double shift, Franke returned home to an empty apartment; her girlfriend was out of town. Later that day, after the girlfriend was unable to reach her, she called a neighbor, who found Franke dead just inside the apartment door.

She’d been shot once in the head, and her wallet, containing no cash, had been discarded on the floor, according to court documents. Her clothing had been partially removed, and investigators found semen on her body. Police surmised that she had resisted the killer’s attempts to rob and rape her.

Police took a sample of the semen and submitted it to the state crime lab, which developed a profile and entered it into a national criminal database. There was no match. They took DNA from dozens of people ─ potential suspects, as well as friends, relatives, co-workers, neighbors, acquaintances and witnesses ─ and compared their profiles to the DNA found at the scene. Again, no hits.

They tried other forensic methods ─ lifting fingerprints from the apartment, entering a shell casing into a national firearms database ─ and found nothing. Years passed with no progress.

That changed in April 2018, when California authorities announced that they’d used a groundbreaking technique to identify a man they said was the Golden State Killer, a serial rapist and murderer who’d terrorized the state in the 1970s and the 1980s. Law enforcement officials said they’d solved the case by entering crime-scene DNA into an online database called GEDmatch, where people shared profiles purchased from direct-to-consumer genetic testing companies such as Ancestry.com and 23andMe.

Orlando Detective Michael Fields, who inherited the Franke case from a retired colleague in 2012, decided to try the same tactic. He reached out to a Virginia company, Parabon NanoLabs, which had just started helping law enforcement identify unknown suspects by using genealogy websites to find their relatives and build family trees. The researchers, led by Parabon’s top genealogist, CeCe Moore, found two cousins of the suspected killer in GEDmatch and traced their common ancestors to a husband and wife who lived in Valdosta in the first half of the 1900s.

The Valdosta couple had an extremely large family, producing a sprawling family tree. Navigating that thicket left Fields and the researchers at dead ends, unable to go further without getting DNA from more people in the family.

Asking innocent people to voluntarily provide their DNA — known as “target testing” — is an unseen but essential, and thorny, component of investigative genetic genealogy. While police are seeking straightforward information about family ties, the process can also reveal secrets, including out-of-wedlock births and adoptions, ethics and privacy experts say. Subjects may not fully understand how their DNA profiles will be used.

While American courts have ruled that police are allowed to mislead people to obtain evidence, there’s a debate within law enforcement over how honest police should be in seeking DNA from people who aren’t suspected of a crime.

Investigator Matt Denlinger works cold cases for the Cedar Rapids Police Department in Iowa. He used target testing to help solve the 1979 murder of a teenage girl. He says the truth, without including many details, usually works.

“You just go up and tell them what you’re doing. No sleight of hand,” he said. “Most people are happy to help. They know they’re not involved. People get excited to help solve a mystery, if you phrase it that way.”

Jennifer Spears, a cold case investigator with the Seminole County Sheriff’s Office in Florida, said she rarely gets any hesitation from the people she approaches. “I tell them their DNA is only being used in this case to help us determine where we need to be on the family tree,” she said. “Are we on the right branch, or are we way off?”

The Department of Justice requires “informed consent” from nonsuspects before collecting DNA for a genetic genealogy investigation, according to an interim policy published last year. If a law enforcement agency decides that getting such consent would “compromise the integrity of the investigation,” then investigators may obtain the sample covertly, but must first get approval from a judge.

The policy covers cases involving federal authorities, so it does not apply to the Franke case, which was handled by local police. It also leaves unaddressed the use of a false story to persuade someone to provide a DNA sample. The lack of uniform rules opens the process to ethical risks, said Christi Guerrini, an assistant professor in the Center for Medical Ethics and Health Policy at the Baylor College of Medicine.

“Unless circumstances compel us otherwise, we generally want people to be informed as to why they’re being asked to provide DNA to help with the investigation,” she said, adding that she didn’t know enough about Orlando police’s actions to evaluate their handling of the Franke case.

The Orlando Police Department and the State Attorney’s Office prosecuting the Franke case declined to comment.

Fields also declined to talk about his work on the case, but in interviews last year, he shared his general approach to asking people for their DNA. He said he has done it about 40 times, either as the lead investigator on a case, or assisting other police departments.

Fields said his approach depended on the person: how closely related they appeared to be to the unidentified suspect, whether they’d worked in law enforcement, whether they’d done any research on their own family trees.

He said he typically told his subjects the truth, without getting too specific: that there was a murderer or rapist in their family and he needed their DNA to figure out who it was. Other times, Fields said, he used a “ruse.” He declined to say what it was, or why he used it. “But it’s effective,” he said.

Holmes was raised in Valdosta, a small city near the Georgia-Florida border, but met her husband at a restaurant in Orlando, more than 200 miles away. They married and raised six children there, including Benjamin Holmes Jr., who they said was athletic, outgoing, popular and a junior deacon at his church. He didn’t give his parents too much trouble beyond staying out late, they said.

After their children were grown, Holmes, a former nurse’s aide, moved back to Valdosta with her husband, a retired chef. They live a quiet life there in a single-story home behind a screen of pine trees and a chain-link gate. The couple are intensely private. The visit from the detectives in October 2018 upended that.

Fields and his partner, Detective Michael Moreschi, arrived without any advance notice. It quickly became clear that they already knew a lot about the Holmes family.

“They knew my father, they knew my children, they could name every one of my children, where they lived. Everything that they wanted, they had it right there,” Holmes recalled. “Except for my DNA.”

At that point, Fields and his colleagues had collected more than a dozen voluntary DNA samples that had narrowed the search. They believed the killer was one of Holmes’ two sons, according to an affidavit Fields would later file in court.

Among those who’d already given their DNA was Alvin Davis, who said the detectives showed up at his Valdosta home and told him they were trying to identify a woman who’d died in Orlando. They thought she was related to him, and needed his DNA to help figure out who she was.

Davis said he wasn’t worried; he liked the police and wanted to help. ”I got nothing to hide,” Davis, 63, recalled telling them. They swabbed his cheek and left.

The detectives told Cynthia Young, who lives in Miami, a similar story when they came to her door for her DNA.

Young, 63, a retired corrections officer, said she agreed because she understood how DNA could help a police investigation.

“I didn’t have a problem with it,” she said. “I see the good of using DNA.”

Those DNA submissions helped pave a genetic trail that led police to Holmes.

Holmes said she isn’t a very trusting person. But the detectives put her at ease. Before submitting to the swab, she said she joked with the detectives that they might find out that she was related to them.

“I didn’t really think it over,” she recalled.

The detectives then asked her husband for his DNA. He declined and walked away.

“For me to give my DNA to you, you have to come with some kind of papers from lawyers or something,” Benjamin Holmes Sr. recalled. “Just going to walk in out of the blue and say, ‘I want to take your DNA, could you give me a sample?’ No.”

Immediately after collecting Holmes’ DNA, police sent it to the Florida state crime lab, which determined that the suspect was one of her two sons, Reginal Holmes and Benjamin Holmes Jr., who both lived in Orlando, according to the Fields affidavit.

Investigators first focused on Reginal Holmes, following him to work as he installed air conditioning units at a construction site. An undercover officer approached him, got into a conversation with him, and offered him a bottle of Gatorade. Reginal Holmes took it and drove away, with the undercover officers tailing him, according to Fields’ affidavit. When Reginal Holmes threw the bottle into a dumpster, a detective retrieved it and took it to the state crime lab, which obtained a DNA profile and compared it to the crime scene DNA. There was no match, making Benjamin Holmes Jr. the prime suspect.

He was a Wendy’s restaurant manager with a record of arrests dating to 2001, mostly low-level drug charges and probation violations, as well as a domestic violence charge, according to Fields’ affidavit. Officers put him under surveillance. On the second day of following him, officers watched him step outside a friend’s house with a cigar and a beer, then throw them out. An undercover detective retrieved both, and police sent them to the crime lab, which found a match with the DNA from the crime scene.

Based on that link, and a follow-up sample of DNA Benjamin Holmes Jr. provided under court order, police arrested him on Nov. 2, 2018, charging him with shooting and robbing Franke. They did not offer a motive or a connection between the two.

Benjamin Holmes Jr. denied killing Franke, or ever knowing or meeting her. “He has no idea how his DNA ended up at that place,” his lawyer, Jerry Girley, said.

Girley said he was exploring ways to prevent the DNA evidence from being used at trial. He noted that the Franke case was among several in which DNA samples at state crime labs were found to have been contaminated. Lab officials have said that the samples have since been reanalyzed under sanitary conditions, providing profiles that can be used in court.

Girley has also discussed the case with the American Civil Liberties Union, which is tracking it as part of a broader plan to challenge the warrantless collection of DNA from property abandoned by potential suspects.

Girley acknowledged that police didn’t break any laws when they used a ruse to obtain DNA from Holmes. But, he said, the tactic ought to be restricted.

“There should be further evolution of the law to come abreast with the evolution of technology,” Girley said.

After hearing about Benjamin Holmes Jr.’s arrest, the relatives who gave their DNA to supposedly help identify a dead person realized the truth.

Young figured it out after seeing news coverage, which focused on the use of genetic genealogy.

“It bothered me because they came to my house and they lied,” she said.

Young, who knows Holmes but not her son, said that she’s not sure she would have given her DNA if she’d known how it would be used.

“Had they been honest, I would have made a decision whether to give them my DNA or not, and if I chose not to, they could have gotten it by other means,” Young said. “I’m OK with them getting it through other means. But to come to me and just lie to get what they want?”

Davis said he would have given his DNA if the detectives said they were investigating a murderer in his family. He does not know Benjamin Holmes Jr. but has met Holmes. “I just regret that they tricked me to get it,” he said.

Holmes and her husband said that hearing what their son was accused of sent them into a long period of grief and anger that left them little time to ponder the detectives’ story.

“I was so hurt, I don’t think I could have hurt any more if he was dead, if he had been killed,” Holmes said. “That’s just how much I was hurt inside. My heart hurt. I couldn’t sleep at night, I didn’t want to see anybody, I didn’t want to talk to anybody. I was torn up.”

She said that if she knew her DNA was going to be used to investigate a potential murderer in her family, she doesn’t think she would have given it. “I don’t want to get involved — that’s the first thing I would say,” she said.

On the other side of the case is the murder victim’s mother, Tina Franke, a retired nurse’s aide, who remembers her daughter as fearless and exuberant and a natural with children. She spent 17 years wondering if anyone would ever be charged with the murder. She got a tattoo on her right arm of a doodle her daughter once drew; it says “Mom Dad I love you.”

Fields explained to her the basics of how genetic genealogy was used to close the case, but Tina Franke said she didn’t know how DNA was taken from Benjamin Holmes Jr.’s relatives, including Holmes. “I feel bad for her,” she said.

Still, she said she had no problem with the tactic. “I’m glad for the end result,” she said.

She wonders if Benjamin Holmes Jr.’s relatives would feel differently if the situation were reversed.

“If they can imagine their own daughter being murdered and 17 years have gone by and they still don’t know who did it and they have DNA and no one to attach it to,” she said, “I think they’d want them to do what it took to find out who did it.”