She was not a typical student. Before going into law, she’d gotten a Ph.D. in biology. And as a patent lawyer, she specialized in biotechnology inventions, often working with companies that were innovating in molecular biology. Originally from New Zealand, she’d first moved to the United States with her ex-husband, J. Craig Venter, the geneticist who would become known for his work sequencing the human genome.

S oon after completing the course, she began teaching it.

Although she insists that she still considers genetic genealogy a hobby, she’s now talking to various law enforcement agencies about 50 cases involving homicide and unidentified victims.

How did she get involved in criminal cases?

In 2015, Ms. Rae-Venter assisted a detective who was trying to figure out the identity of a woman named Lisa who had been kidnapped as a baby.

Now in her 30s, Lisa had spent most of her life thinking that the man who had abused and then abandoned her was her father. That man had later been convicted of murder. In the course of that investigation, detectives had discovered that her DNA did not match his. So who were her parents? Where had she come from? The man refused to answer questions about her origins.

It took 20,000 hours and the assistance of more than 100 volunteers. But ultimately Ms. Rae-Venter used her techniques find the woman’s birth name, Dawn, and connected her with her grandfather, who was her closest living relative interested in a connection.

Ms. Rae-Venter was able to narrow Lisa's likely father down to a grouping of brothers. All had been married at the time of her birth and those that could be located refused DNA testing. Still Lisa had gone from knowing nothing about who she was to holding a family tree containing thousands of people.

Mr. Holes learned about Ms. Rae-Venter’s work on that case in 2017. If she had been able to figure out this girl’s identity with so few clues, couldn’t she also identify someone using well-preserved semen?