But with a booming cottage industry of companies courting the business of cold case detectives, other law enforcement agencies around metro Atlanta say they are exploring use of the technique.

“I would predict police departments, especially (those) with cold case units, are going to take advantage of this,” said Dean Dabney, a criminal justice professor at Georgia State University. “It’s just going to keep growing.”

For the family of Lorrie Smith, a musician and church youth counselor, it’s brought a measure closure they’d come to doubt was even possible.

But forensic genealogy isn’t the be-all and end-all in most cases, experts say, because it’s labor intensive and can be costly.

And, increasingly, skeptics are raising questions about whether police and lawmakers are fully considering the ethics of the widely unregulated technique as it spreads rapidly across the U.S.

The process

Generally speaking, criminal forensic genealogy searches work this way:

Police hire a firm to examine an unknown suspect's DNA and convert the characteristics within into a digital format. In Lorrie Smith's case, police told Channel 2 Action News the company was Parabon, which had for some time been known for other DNA work but announced a new forensic genealogy wing just a month after the arrest in the Golden State Killer case.

The company then uploads the DNA into an ancestry database. Likely, it's GEDMatch, which has been the most open to police. The site requires that they are investigating a homicide, a sexual assault, or trying to identify human remains. (Ancestry.com says it will release user data to police only in response to "a valid trial, grand jury or administrative subpoena." 23andMe says it won't give cops data unless through "a valid court order, subpoena, or search warrant.")

A search is run of DNA that consumers have uploaded in their family tree pursuits. The site returns a list of potential relatives, which could be thousands of people. The list must then be whittled down by investigators, which can take months, until they find a third or fourth cousin who’s put their DNA in the system.

From there, investigators have to determine what relative could be the suspect, and get DNA from the suspect, sometimes from a drink can or napkin tossed in a public trash can.

In the Fulton case, investigators got a warrant for Lee’s DNA. Police have said they found Lee at a hotel in Alabama, and his DNA matched the blood from Lorrie Smith’s home.

An attorney for Lee did not return a phone call seeking comment.

Lorrie Ann Smith

“It’s was a long wait, a long, long wait,” father James Smith said, adding that he’d never seen or heard of Lee until the arrest. The parents still aren’t sure — and police haven’t said — why he would allegedly kill their daughter, a deeply religious woman who loved to help people.

The promise and the questions

Since the Golden State Killer case brought forensic genealogy into the spotlight last April, authorities say they've solved about three dozen cold cases across the country. Just days ago, police in Alabama announced they'd arrested a man in the deaths of two high school students who were slain in 1999. In a few cases, including the death of a Pennsylvania school teacher, defendants identified through the method have pleaded guilty. No cases have gone to trial.

Some critics want to see the practice regulated.

Natalie Ram, who teaches bioethics and law at the University of Baltimore, said she wonders whether searching people’s DNA to get to their relatives, who haven’t submitted their DNA, is unconstitutional under the Fourth Amendment, which bars unreasonable searches and seizures.

Ram is also worried because, though GEDMatch asks police to limit searches to investigations of certain types of cases, there are no laws holding them to that. “It’s kind of like the Wild West,” she said.

Dabney of GSU points out that those who don’t want their DNA used in such a way can ask for it to be removed from the databases. He doesn’t think a Fourth Amendment claim would hold up, because what investigators are ultimately doing is constructing a family tree, which they could theoretically do without DNA, though it would be far, far more difficult.

He also said he finds it unlikely authorities would use forensic genealogy to investigate cases other than homicides, rapes and unidentified remains, if for no other reason than how time consuming the process is.

Augusta case raises concern

Already, controversial cases have come up. After a fetus was found last May at a wastewater treatment plant in Augusta, officials decided to use DNA to find the mother. Richmond County Coroner Mark Bowen said he just wanted to make sure the mom was OK, but he also wondered if the fetus could've been aborted illegally, according to the tech and science news website The Verge.

The fetus turned out to have been miscarried, according to the Augusta TV station WRDW. Still, the case had genealogists concerned all the same because it presented a divergence from the common uses of DNA, which until 2018 had generally been used to identify a person, not a relative of the person who might've committed a crime.

Had the mother been charged with criminal abortion, the case would've also diverged from the idea that police should use familial DNA searches for investigating only violent crimes against persons. Georgia law regards unlawful abortion as a "moral" and "public health" crime, not a crime against a person (that could become murky after passage of this year's "heartbeat bill").

How ever police use of the technology evolves, people like Lorrie Smith’s parents seem unlikely to be swayed from their belief that it can do good.

What matters to them is the man believed to be responsible for their daughter’s death sits in the Fulton County jail, facing his fate, finally. The fact that the killer’s blood ultimately led to Lee’s arrest brings them comfort, especially because they figure it was Lorrie Smith’s fighting back that spilled that blood.

In a way, Jean Smith said, her daughter helped solve her own murder.