In simple terms: the genealogy database was large enough, and the technology was developed enough, to be useful for this purpose only in the years immediately before the investigation applied it. Holes’s decision to contact Rae-Venter in March 2017 came at what turned out to be the right historical moment — a moment when the method was technically feasible and when the databases were large enough to produce useful results.
If the same inquiry had been made five years earlier, the databases might not have been large enough to contain relatives of DeAngelo’s family. If it had been made ten years earlier, the technical infrastructure for the comparison might not have existed in its current form.
## The Genealogical Work in Detail
Barbara Rae-Venter holds a Ph.D. in biological sciences from the University of California, San Diego, and a law degree from the University of California, Berkeley. She worked in patent law for years before turning to genetic genealogy, which she pursued initially through her own family history research and then as a professional practice. She had developed expertise in cases involving adoptees seeking to identify biological relatives — cases where the starting point is a DNA profile without a name, and the task is to build a family tree that produces one.
This background made her specifically suited to the task Holes brought to her in March 2017. The Golden State Killer case presented an analogous problem: a DNA profile without a name, and the task of building the investigative pathway from one to the other.