‘FORENSIC GENEALOGY’ IS SOLVING COLD CASES
Emerging field is able to link DNA testing and family histories
SANTA CRUZ >> When they’re planning to rob a liquor store, most criminals think to wear gloves and cover their faces. But few of them commit to shaving their heads to avoid leaving behind even a single strand of hair.
In the future, however, they may want to add that task to their modus operandi. Packed with DNA, hair is quickly becoming a powerful source to help catch lawbreakers.
Hair has been notoriously tricky to analyze, but a new approach by UC Santa Cruz researchers — pulling DNA from samples that are damaged or contaminated — is expanding the available pool of forensic evidence. DNA and ancestry records are now being used together to build family trees to identify rotten apples among their branches.
But while the rapidly emerging field of “forensic genealogy” is solving longcold cases, it’s also raising thorny ethical questions about privacy. We all leave traces of ourselves wherever we go.
“Law enforcement gets excited about hair because often it’s all they have in the way of evidence,” said genealogist Barbara Rae-Venter, who has teamed up with Richard “Ed” Green, an associate professor of biomolecular engineering at UC Santa Cruz. Green, known for his work on the remains of Neanderthals, has developed tools to decipher ancient DNA — often hundreds of thousands of years old.
Before gaining recognition by identifying Joseph James DeAngelo, the suspected Golden State Killer, Rae-Venter was a retired patent attorney practicing genealogy in her Monterey Peninsula home.
While reconstructing the family tree of a woman kidnapped as a child and later abandoned in a Scotts Valley mobile home park, RaeVenter had linked the alleged abductor, Terry Peder Rasmussen, to the four unsolved Bear Brook murders in New Hampshire in the
late ’70s. DNA from the victims’ bones, however, was too damaged to establish the identity of the victims, and Rasmussen had died in California’s High Desert State Prison in 2010.
Rae-Venter was stuck, unsure of how to unravel the case, when she read a news story about Green.
“I got so excited because he kept talking about hair,” Rae-Venter said.
Because hair doesn’t degrade much over time, she had samples from each victim but no way to analyze them. Hair had been useful evidence only if its root, pulled from the follicle, was still attached.
Green and his team, however, had recently pulled usable DNA from a strand of hair without its root, long thought to be impossible.
“Forensic samples can be seen as really easy ancient DNA samples (to analyze) because they’re so much younger, even in cold cases,” Green said during a recent interview in his UCSC office.
Green and Rae-Venter began analyzing hair from the Bear Brook murders in 2017 and ultimately identified three of the four victims last June. Using similar methods, Rae-Venter then named DeAngelo, then 72, who is now awaiting trial for a series of murders committed in California from 1976 to 1986.
The duo’s success has prompted Green to co-found a company, Astrea Forensics. The Santa Cruz startup has already solved dozens of cases and continues to work on dozens more.
“There is a market for this,” Green said. “There’s a public service demand and a larger social mission.”
For the last few decades, profiles of criminal suspects have been generated through a process called DNA fingerprinting. It relies on a person’s unique pattern across 20 genetic markers — short sections of DNA that vary between individuals. Suspects entered into the FBI’s criminal database are compared against 16 million profiles.
But DNA from cold cases generates hits less than 1% of the time. The reason is that the FBI’s system needs high-quality, detectable DNA from a single person — a tough and often unreachable standard. Many cases go cold because the DNA is old or damaged, contaminated by bacterial DNA or mixed with material from multiple individuals.
Astrea’s proprietary methods reconstruct entire genomes — the total genetic material in each cell — from DNA fragments. By sequencing the whole genome, rather than just 20 markers, forensic genealogists can often identify people the FBI cannot.
Access to DNA data is growing. Companies such as 23andMe and Ancestry. com have been sequencing the genomes of more than 30 million people in the past decade.
The firms’ databases are private, but customers can upload their profiles to thirdparty sites like GEDmatch, a Florida company that allows its users to compare genetic testing results from different DNA companies and use genealogy to reconstruct family trees.
Applied to forensics, it becomes an amazing technique.
The U.S. Department of Justice recently released its first interim policy on forensic genealogy, an initial step toward standardizing the practice. The policy states that investigators of violent crimes who have exhausted traditional methods such as fingerprinting may now consider genealogy.
In Santa Clara County, criminalist Kevin Kellogg at the district attorney’s office has solved several cold cases with the help of Parabon NanoLabs, a Virginia company that specializes in forensic genealogy. The cases include the 1973 strangling murder of 21-year-old Stanford graduate Leslie Marie Perlov.
John Arthur Getreu, a 74-year-old former Boy Scouts leader and “exalted ruler” of the Fremont Elks Lodge, now stands accused of killing Perlov and dumping her body in the Palo Alto hills. And as a result of DNA tests, Getreu is also charged in San Mateo County in the 1974 strangling death of 21-year-old Janet Ann Taylor, the daughter of former Stanford football coach Chuck Taylor.
But as the field advances, critics of forensic genealogy are raising ethical issues. They argue that as more people use DNA kits and databases are built out, police could eventually track anyone.
Rebecca Jeschke, an analyst with the Electronic Frontier Foundation in San Francisco, warns that access to databases could prompt police to “over-collect” genetic material.
“DNA holds private and intensely personal information,” Jeschke said.
In response to public concern, GEDmatch changed its default policy last May by excluding all 1.25 million profiles from law enforcement matching. Users must now “opt-in” after reading new explanations about how their data will be used. As a result, investigators can now access just 190,000 profiles.
Rae-Venter said many cases that she solved “would remain cold under these new restrictions.”
Still, many ethical and privacy experts believe that a way can be found to balance the new technology’s risks and rewards. Jeschke, for instance, suggests that the solution might be a system of checks on law enforcement’s access to databases, including “added oversight” from judges.
“We’re still finding our way through to where the boundaries are going to be,” said bioethicist Amy McGuire of Baylor College of Medicine in Houston. “But if it’s done well, if it’s done right, I feel fairly convinced that the actual privacy risks are fairly minimal.”