Genealogy databases that allow DNA profiles to be compared with distant relatives have helped investigators solve major crimes, and authorities in Arizona are now considering using that approach in the search for Nancy Guthrie.
Pima County Sheriff’s officials said DNA collected so far in the investigation has not turned up matches in CODIS, a national criminal justice database that contains DNA profiles from convicted criminals and, in some states, people arrested for certain crimes. The department said Tuesday that investigators are looking into additional “investigative genetic genealogy” options for DNA evidence to check for matches, with CODIS described as only one of many databases available.
The department later said Wednesday that biological evidence from Guthrie’s Tucson-area home was being examined and that DNA profiles were at a lab for analysis. Guthrie, the mother of NBC “Today” co-anchor Savannah Guthrie, has been missing from her home since Feb. 1.
Authorities have also pointed to other leads in the case. The FBI said gloves found about 2 miles (3.2 kilometers) away appeared to match those worn by a masked suspect captured on a porch camera, according to the AP report. As the search continues, investigators are weighing whether DNA evidence can be linked to people in consumer genealogy databases, which can sometimes lead police to a suspect by identifying distant relatives.
Ruth Ballard, a geneticist in California who specializes in DNA and has testified in hundreds of court cases, said investigators could move faster if the DNA evidence is usable. “It’s a fantastic tool,” Ballard said. “If it’s a good quality sample and they’re able to get a profile, they could find a hit on that fairly quickly.”
Ballard said the quality of the DNA sample and its source can matter when pursuing matches in genealogy databases. “It does require a much better sample than CODIS searching does,” she said. She also pointed to limitations and uneven coverage in how different groups appear in these databases, saying, “The databases are not equal in terms of ethnic distribution. It’s comparatively easier to find a Caucasian because more have uploaded their data and there are more family trees to mine.”
The AP report also described how genealogy databases have been used in other major cases. It cited the use of GEDmatch in the investigation of the so-called Golden State Killer, where investigators used DNA from crime scenes to find a distant relative, build a family tree, and identify Joseph DeAngelo Jr., who pleaded guilty in 2020 to 13 killings and dozens of rapes in California in the 1970s and ’80s. DeAngelo is serving life in prison without the possibility of parole, the report said.
In Idaho, the report said DNA from a knife sheath helped investigators identify Bryan Kohberger in the 2022 killings of four University of Idaho students. It said police used genealogy sites to build a family tree and pulled trash from the Pennsylvania home of Kohberger’s parents to make a connection. Kohberger pleaded guilty and was sentenced to life in prison, according to the report.
The report noted that genealogy companies have different policies for complying with law enforcement requests. Genealogy sites Ancestry, 23andMe and MyHeritage say they can be asked to comply with court orders seeking information, while GEDmatch said its policy is to ask users if they want to opt in to allow police to look at their data. The Associated Press said it emailed the companies asking if they have a role in the Guthrie investigation.
Barbara Rae-Venter, an expert genealogist who worked on the DeAngelo case, said advances in genetic genealogy do not always produce quick answers. “I’ve solved cases in less than eight hours where people shared a lot of DNA with the suspect. Other cases, you’re still working on them two years later. This could take awhile,” Rae-Venter told CNN, referring to the Guthrie effort.