In 2014, the market for mail-in DNA kits like those from Ancestry and 23andMe was much smaller. The technology was much simpler, too. Genealogists interested in DNA were usually looking only at the tiny subset of a person’s DNA that could be easily analyzed at the time: the Y chromosome, which is always passed from father to son, or mitochondrial DNA (mtDNA), which is always passed from mother to child. The Belle in the Well was a woman, so she didn’t have a Y chromosome, but she did have mtDNA.

This gave Nenni an idea. He uploaded Belle’s mtDNA to a public database maintained at the time by Ancestry and got 50 to 60 matches. He messaged them all, hoping that their family history or lore might hold a clue that would lead him to Belle’s identity. But the problem with mtDNA is that people who share a great-great-great-great-grandmother might have all the same mtDNA markers—but be so distantly related that they have little information to share. No one who responded to Nenni knew of a missing person in their family. Most people did not respond at all.

Very quickly, Nenni hit a wall. He realized that to actually trace enough relatives to ID her using genealogy, he needed to do more advanced analysis of autosomal DNA, which contains far more genetic information than the Y chromosome or mtDNA. (Autosomal DNA refers to the 22 pairs of chromosomes other than X and Y.) For this, Ancestry required saliva—a large amount of it.

“At one point, I had delusions,” Nenni says. “If I could get ahold of Belle’s DNA, I’m gonna put it in some distilled water in one of Ancestry’s test kits and send it to them and not say anything about it.” He never did do that. The company took its mtDNA database offline in 2014 as part of the industry’s shift to autosomal DNA, and Ancestry’s $99 tests today are based on autosomal DNA. Ancestry has been reluctant to work with police, and it has not allowed law enforcement to search its current autosomal-DNA database.

It was not until 2017, when Murray, Nenni’s collaborator, met a forensic genealogist named Colleen Fitzpatrick at a conference, that the team saw a way forward again. That same year, Fitzpatrick and Margaret Press, a hobbyist genealogist and crime writer, had co-founded a nonprofit called the DNA Doe Project to identify John and Jane Does. They were looking for pilot cases. The Belle in the Well became one of the first four cases for the fledgling nonprofit in June 2017.

The DNA Doe Project has since solved 12 Doe cases, but Belle’s case was the hardest and took the longest, at 14 months. “This case is a big deal for us,” Press says.

Press personally spent sleepless nights researching the Belle in the Well. When I visited her home in Sebastopol, California, last summer, she pulled out a stack of hand-drawn family trees for the unidentified woman. The case was so difficult because of endogamy, or the practice of marrying within a community. Belle’s ancestors in West Virginia, which is just across the river from Ohio, where she was found, appeared to all be related to one another in several ways.