Barbara Rae-Venter is a genetic genealogist who helped crack the unsolved case of the Golden State Killer. She works with law enforcement to identify victims and suspects of violent crimes. (Brian L. Frank photograph)

LEBANON — For all the crimes that forensic genealogy is helping to solve, some mysteries continue to elude DNA and data experts, the relatively new field’s foremost expert told scientists during a symposium at the Geisel School of Medicine on Thursday.

Take the case of the Allenstown Four — a woman and three young girls whose dismembered bodies were found bound in barrels in a swampy part of central New Hampshire’s Bear Brook State Park in 1985 and 2000. While California-based genetic genealogist Barbara Rae-Venter helped investigators connect a drifter named Terry Peder Rasmussen to the killings in 2017, “the identification of (three of) the victims is still pending,” she said.

Rasmussen fled New Hampshire in 1981 with a girlfriend, Denise Beaudoin, and the girlfriend’s young daughter, Dawn. He later abandoned Dawn who he had been calling “Lisa” in 1986. Rasmussen died in prison in 2010 after his conviction in another murder case, under one of many pseudonyms.

Rae-Venter’s work in the case, which began in 2015, did help the kidnapped girl, now in her late 30s, learn her identity and find relatives in New Hampshire.

Rae-Venter’s contribution to the Allenstown case led a veteran detective in the Contra Costa County, California, district attorney’s office to ask for her help in 2017 to solve the cold case of the so-called Golden State Killer.

With a DNA profile built with a semen sample from the scene of one of the killer’s crimes, Rae-Venter used GEDMatch, an open-data personal-genomics database and genealogy website, to “build a lot of family trees” through the use of birth records, newspaper clippings, social-media profiles and family tree data, she said.

“In 63 days with five of us working pretty much around the clock,” Rae-Venter and investigators from the DA’s office and the FBI narrowed the field to a former policeman, Joseph DeAngelo, who was arrested on April 25, 2018, and who is now awaiting trial for a series of 13 murders and many rapes that terrorized a stretch of California between Sacramento and the Bay Area in the late 1970s and early 1980s.

The ensuing publicity from the Golden State Killer case led law-enforcement agencies around the country to consult Rae-Venter for help in some 50 cases, ranging from homicides to kidnappings. She’s also begun conducting workshops and delivering lectures, such as the one on Thursday.

“At one of my presentations after the Golden State Killer arrest, a woman came up to me afterward and said, ‘Thank you! Thank you! Thank you!’ ” Rae-Venter said. “She had three friends who had been raped by this guy.”

It’s a life RaeVenter never quite imagined when, after retiring in 2005 from a career as a patent attorney in intellectual property cases, she started doing genealogical research on her own family. Born in New Zealand, she traced her history to the British Isles, Canada and Australia. In the process, she learned to do testing with 23andMe, Ancestry DNA and other tools.

The personal searches led her to take a course on DNAAdoption.org on how to use genetic testing to find family, and she wound up teaching the course herself. She also became a volunteer “Search Angel” for DNAAdoption, which led her to the case of “Lisa” and the Allenstown Four.

“It’s been a whirlwind ever since,” Rae-Venter said after the lecture. “I’d been doing some educational presentations and workshops before all this happened but nothing quite like what this has become. It’s been evolving and will continue to evolve. For now, when I’m not working on these cases, I still want to focus on education.

“I try to pick and choose.”

David Corriveau can be reached at dcorriveau@vnews.com and at 603-727-3304.