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Ideas, Progress & the Future

The missing piece: Exploring the use of private DNA databases in police investigations

Content warning: This article discusses confronting issues, including murder, missing persons cases, trauma and sexual assault.

Chances are, you’ve seen the ads. Just swab the inside of your cheek, send it away for testing, and you can discover your cultural heritage, maybe find out a little more about your grandparent’s parents, or in some cases, even discover previously unknown siblings or other relatives.

What many users might not know, is just how your genetic material could be used by police to solve major crimes; do consumers truly understand what they’re signing up for when handing over their DNA?

After several discussions on the topic, Dr Sally Kelty, a UC Senior Lecturer and Dr Nathan Scudder, an Adjunct Associate Professor with the University’s Faculty of Health, decided to explore the public’s perception of police using private DNA databases to solve serious crimes. Stemming these conversations, an Honours project was advertised, and Ms Alexandra Quinton joined Sally and Nathan in their investigation as part of her Psychology Honours in 2020.

The advancement of forensic/investigative genetic genealogy in recent years has allowed police to close decades-old cold cases — think of the likes of The Golden State Killer in the United States. In 2018, he was charged for a spree of murders that took place from 1974 to 1986. After an intensive police investigation that spanned nearly 30 years, it was a lead generated from a private DNA database that finally allowed police to find the identity of the serial killer.

There’s also the case of the ‘Buckskin Girl,’ an American murder victim, who for over 30 years was known only by an item of clothing she wore – a distinctive buckskin jacket. After cross-matching her DNA through a consumer database in 2018, investigators received an intelligence lead that allowed them to finally put the missing pieces in the puzzle and find her identity — Marcia King.

These are both examples of cold cases where all leads have been exhausted; where investigators might have had the suspect’s or victim’s DNA for years, but the DNA didn’t match anyone — now, we’re seeing, that’s no longer the end of the road for these investigations.

How does it work?

To begin, investigators upload their unknown DNA profile to several commercial databases, which cross matches the unknown DNA against its library of consenting users and generates a list of the closest genetic matches.

Investigators will then begin to build some of the matches’ family trees backwards in time using traditional genealogy techniques, until a common ancestor is uncovered. Then, they will build the family trees forward from those ancestors, identifying every descendant possible. Once the trees have been fully built out, investigators look to identify candidates that might match the unknown DNA sample based on factors such as age, location and gender.

“To get this data five or ten years ago, you would have been going through archives, through records in libraries, to trace those family trees. Now, from the comfort of your own desk, you can start to research someone’s ancestry. What could have taken months and months previously, can now, in theory, take a matter of days,” Nathan says.

“We looked at advanced DNA technology in a law enforcement context – the technological changes and what they mean for privacy, for public trust in policing, and how we can ensure those new capabilities are available to solve cases.”

The research

Following completion of the Honours project, Alexandra, Sally and Nathan worked to turn the Honours paper into an article ‘Attitudes towards police use of consumer/private DNA databases in investigations’ which was published in the journal of Science and Justice in May 2022.

For their research, the trio recruited 438 adults and in a series of questionnaires, tested participants’ perspectives on how police use private DNA databases, and for what type of crime this use is most acceptable.

The trio developed five hypothetical crime scenarios ranging in severity from homicide to drug use offences. Members of the public were asked how acceptable it would be for police investigators to access private DNA databases to identify suspects or victims of these crimes.

The study found that public support depended on the type of crime — the more serious the crime, the more the public supported police going to these lengths to solve it.

83.5 per cent of participants supported the police cross matching DNA with private databases in cases of sexual assault, 83.2 per cent for homicide and 85.2 per cent for the identification of unidentified human remains.

Participants were less supportive of police use of private DNA databases for robbery (62.8 per cent) and illicit drug-use cases (58.9 per cent).

The findings suggest that while support depended on crime type, there was consistent support for police to gain informed consent from database users before using consumer DNA databases in investigations, across all crime types.

“For homicide cases, think the Golden State Killer for example, 83 per cent of this sample supports the police using forensic genealogy when all other links have been exhausted to try to solve the crime,” Nathan says.

“We canvassed a whole range of crime types, so we can map out where those limits might be.”

In the second part of the study, the researchers attempted to measure whether positive attitudes towards the police, the law and the criminal justice system influenced the level of public support for police investigators to use this technique.

They found that the more positive the participants’ attitude towards the police, law and the courts, the higher the support for police to use private consumer DNA databases for investigations. They also found that the higher participants attitudes were towards retributive punishment, the greater their support for the use of private databases to be used by police (controlling for both age and gender).

The implications

Currently, quite a few (although not all) private DNA databases allow for the data to be used in investigations of murder, sexual assault and missing persons cases, which largely fits in with the findings of the study. The issue is that a grey area exists between what crimes are accepted and what crime doesn’t neatly fit neatly into a specific crime category.

“This is an interesting and tricky policy space. Something that we’ve already seen with this technique, is this argument about the slippery slope and how things can move,” Sally explains.

“Take, for example, a case where a grandmother was beaten horribly during a burglary. The investigator rang up the database administrator and requested to match a crime scene DNA sample of the suspect to data held in the private database.  This created backlash because effectively, although the crime is heinous, it might breach the terms and conditions of the private database, as aggravated burglary may not be on the approved crime type access list.”

“We need to have firm guidelines and scope around the use of forensic genealogy, to avoid blurred lines,” Nathan says.

“Gradually you might find that this technique is used in more and more cases, and we reach the point where the public think ‘we never agreed to this.”

The researchers hope that the study will help shed light on public perception of the technology, to help guide legislature around its use.

“It’s important to ensure we understand the public’s expectations on how this technology will be used. The use of this technique is, on a number of levels, dependent on public support – if people disapprove, they’ll just opt out and you won’t be able to match against their genetic information, so this technique could quickly become unviable,” Nathan says.

What this means for the future of the forensic sciences requires more exploration, as governments begin to develop legislation to guide ethical usage of this new technology.

Although Nathan, Sally and Alexandra have completed this part of the project, it’s by no means the end of the road for their research in the field.

“As these cases are solved, particularly these longstanding cold cases, there's the opportunity to go back and review why they remained unsolved for so long,” Sally says.

“Many countries have national databases for missing persons cases. The DNA is there, and the body turns up. In theory, it should be straightforward to match these up. So why do people remain unidentified for 20, 30 or 40 years? That's the next area of study that we’ll be exploring.”

Words by Kelly White, photos by Cottonbro

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