How genetics revealed the identity of the Golden State Killer—and the unsettling ethical fallout

 February 06, 2023

Authorities in California detained one of the most heinous serial killers in US history in April 2018. Between the middle of the 1970s and around 1986, a guy who went by the aliases "East Area Rapist," "Original Night Stalker," and "Golden State Killer" carried out at least 13 homicides, more than 50 rapes, and 100 burglaries. Local and federal investigators looked for him for around 40 years. Former police officer Joseph DeAngelo, the actual offender, had never been the subject of suspicion. In the end, Barbara Rae-Venter, a retired patent attorney, put in around four months of labour to use investigative genetic genealogy to find the offender (IGG).

IGG entails identifying people by building intricate family trees from genetic data that people have contributed to consumer DNA databases and public sources, typically for ancestry and family history research. The method wasn't used to solve the Golden State Killer case for the first time. Even so, it wasn't Rae-first. Venter's Her introduction to the field of criminal justice involved Lisa Jensen, a little girl who had been kidnapped and had no memory of her past—not even her real name. In order to locate Jensen, Rae-Venter and other volunteers from a group that assists people who were adopted in finding their biological parents applied their expertise. It took approximately a year for her true identity to come to light, and that knowledge led detectives to conclude that Terry Rasmussen, the man who kidnapped Jensen, was responsible for a bloody string of murders.

As word of Rae-accomplishments Venter's spread, Paul Holes, a California detective who desired to solve the Golden State Killer case before retiring, became interested. This inquiry, unlike Jensen's, required sleuths to fabricate a profile using crime-scene DNA from an unaware database participant—the alleged murderer—without that person's permission. That is forbidden by the majority of DNA database businesses, including 23andMe and Ancestry. However, GEDmatch's terms of service did not specifically prohibit law enforcement searches. FamilyTreeDNA, a different business, agreed to construct and upload the Golden State Killer's profile covertly.

The attention is on genealogy

Rae-Venter describes her role in identifying Jensen, Rasmussen, DeAngelo, and other others in "I Know Who You Are." It is a compelling tale that details the countless hours spent searching through people's family ties to find killers and identify bodies. It was co-written by bestselling author Alex Tresniowski. However, the book falls short when addressing the moral conundrums that Rae-acts Venter's have triggered.

After DeAngelo's arrest, IGG came under intense scrutiny. Rae-Venter was one of the first to actually break the glass and employ this technique, even though genealogists were aware that it could be used to solve murders. Some people welcomed IGG as the greatest scientific development in criminal justice since the development of DNA evidence. Rae-Venter was chosen by Nature as one of the ten scientists who mattered that year.

However, there was a backlash as law enforcement officials began stretching the limitations of the tool's use. In May 2019, it came to light that detectives had uploaded a DNA sample from a non-sexual assault to GEDmatch for another investigation. The action was against the site's amended terms of service, which restricted law enforcement agencies to reporting homicide and sexual assault as the only two types of crimes. That gave detractors the impression that their concerns about a slippery slope were well-founded. In response to user ire, GEDmatch reversed course and now only permits law enforcement officials to search the data of those who have given their explicit authorization. In August of that same year, The Wall Street Journal's investigation on FamilyTreeDNA's covert arrangement with investigators produced additional confusion.

The field of genetic genealogy started to become divided over issues of transparency and privacy. Users of the website weren't necessarily aware of it, but law enforcement authorities were looking up personal family information in ways they weren't particularly expecting. Genetic genealogy "was developed for reuniting families, and now it is being used effectively to encourage families to put their members in jail," as one genealogist put it in a news report for The Atlantic.

These worries are dismissed by Rae-Venter, who claims that the horrifying nature of the crimes being investigated provides sufficient justification: "It simply did not strike me as a complicated ethical issue." She cites IGG detractors but skips over their arguments about where to draw the line when using the approach. She mentions in passing, for instance, the issues with using IGG to locate the remains of abandoned infants in an effort to track down and prosecute the mothers. She doesn't completely take into account, however, what these prosecutions entail for justice and public safety: research has shown that neonaticide is more frequently caused by social isolation and a lack of access to healthcare than by violent criminals.

Rae-Venter notes that the majority of cold cases to which IGG is used include white victims of homicide or rape, demonstrating a bias in law enforcement. But she also points out that IGG will be most successful at identifying white suspects because white people are overrepresented in consumer DNA databases. She oddly calls this a "reverse prejudice," presumably in reference to the institutionalised racism in US law enforcement that results in disproportionately high rates of incarceration for people of colour. It is concerning that she spends time talking about how to deal with this restriction but not with others in IGG.

Her casual attitude toward such delicate subjects when discussing the IGG's ethics hampered an otherwise interesting work. IGG is an effective tool. Rae-Venter believes it has resolved more than 1,000 unsolved cold cases. And as the industry expands and consolidates, moving from the purview of amateurs and volunteers to a select few well-funded corporations, it's important to not just retell the specifics of its rise but also to analyse its flaws and abuse potential in greater depth.