Behind the Forensic Investigative Genetic Genealogy that helped charge alleged child rapist Robert Wayne Kwan
Updated ,first published
Robert Wayne Kwan’s thumbs, forced together by handcuffs, twitched in fits and starts as detectives walked him down a long bend in a grassy driveway towards waiting police cars in South Kempsey, north of Port Macquarie, on Wednesday.
The 77-year-old alleged child rapist is accused of a series of historic sex crimes spanning more than a decade, from the targeting of an 11-year-old girl in Sydney’s west in 1991 to the sexual assault of a 26-year-old woman in Devil’s Hole Reserve near Dubbo in 2002.
Just two days after Kwan’s arrest, police swooped on another alleged rapist in the Northern Rivers, a quarter of a century after his alleged crimes. The arrests mark the arrival in NSW of a technology that has jailed legendary serial killers, freed those wrongly convicted of murder and given dignity of personhood to nameless bones.
The investigative tool, called Forensic Investigative Genetic Genealogy (FIGG), relies on people who spit into a tube for commercial DNA testing, choosing to ignore privacy concerns and make their data available to researchers.
They become “genetic informants” who help police build extensive family trees that will lead them to alleged perpetrators. Kwan’s was the first arrest in NSW as a result of the technology.
The second came barely 48 hours later on Friday morning, when police arrested a 73-year-old man at a Murwillumbah service station over a separate wave of sexual assaults on the Central Coast in the 1990s.
The alleged crimes included the assault of a 52-year-old woman while sunbathing; Violent assault on a 16-year-old girl at Budgewoi Beach; and another example of a naked man running towards three young girls on a bush path near Killcare. A 16-year-old girl tripped and was sexually assaulted.
For decades these allegedly horrific acts went unpunished. Until FIGG finally led the police to a suspect.
Here’s how it works. Traditional genetic profiling targets parts of human DNA where sequences of four basic letters (A, C, G and T) are repeated all the time. For example, everyone has a repeating sequence “AGAT” on their third chromosome. However, the number of repetitions of this sequence varies from person to person and serves as a kind of genetic “fingerprint”.
Standard DNA testing focuses on about 20 of these sequences, called short tandem repeats, or STRs, and the pattern of these repeats can match a suspect’s DNA to a drop of blood at the scene.
However, a problem arises when researchers do not have a reference DNA sample. For example, police took DNA samples from Kwan’s alleged crimes but found nothing to match them.
This is where FIGG comes into play. Rather than focusing on a handful of STRs, the test detects a different type of DNA variation called single nucleotide polymorphisms, or SNPs (pronounced “snits”). These are single-letter differences at specific points in our DNA – you might have an A, someone else might have a G – and using special sequencing technology we can detect more than a million of them.
The key advantage for detectives is that this DNA map, which includes more than a million SNPs, is sensitive enough to detect someone’s very distant relatives (third or fourth cousins, for example). (Think about this – do you know who your fourth cousins are?) Finding family can help connect anonymous DNA to a real person.
To do this, researchers match a perpetrator’s or victim’s DNA profile to distant relatives using online genealogy databases of people who have used commercial ancestry tests and given permission for their data to be used by law enforcement. Their database contains approximately 1 million to 2 million genetic profiles. This is exponentially larger than the DNA databases that law enforcement has.
When police find a relative, the investigator turns to genealogy—part genetic analysis, part family history sleuthing—to create a family tree that connects the owner of the DNA to distant relatives in the database.
By scanning back through generations to find the last direct ancestors shared by the person of interest and their identified relatives, experts narrow down the search to a specific branch of the family tree. The process can take days, and in some cases years. This is how detectives can now find the owner of an unknown bone or semen sample.
That’s how FIGG caught Kwan. An SNP profile was created using DNA collected after his alleged crimes more than two decades ago. This profile matched a relative in genealogy databases. Police then used what they knew about Kwan’s gender, age and location to prune the branches of the family tree until only one person remained as a suspect.
This process began in 2018 when the serial killer was identified as former California police officer Joseph James DeAngelo Jr. He became famous for bringing down the Golden State Killer by revealing who he was. Human identification expert Dr. As Jodie Ward points out, FIGG brings decades-old cases cold and solvable.
Take the “woman on the wall” example. Her decade-old remains were discovered by cleaners behind a wall at a unit complex in Brisbane in 2022. He left behind a glass eye, prescription glasses and size 10 clothes. But there was no DNA match in the police database, and there was no associated missing person report.
Using FIGG, police and forensic experts, including Ward, determined the remains were those of 38-year-old Tanya Glover. A woman was arrested in Glover’s death last year.
“What might be the cost of restoring one’s identity?” DNA forensic expert Ward said: “You respond to families, you ensure the deceased is buried with dignity, you keep the community safe as criminal investigations may be opened.
“Currently DNA testing is only offered by law enforcement or government forensic laboratories in Australia and unfortunately not everyone has access to these technologies.”
The process is expensive, about $10,000 compared to routine DNA testing, which can cost $100, he said. That’s why in 2024 Ward founded Forensic Human Identification Co., a social enterprise that provides the only independent end-to-end FIGG service in Australia.
Through this initiative, Ward aims to help families find missing loved ones, exonerate the wrongfully convicted, advance causes for missing First Nations people, and use techniques borrowed from ancient DNA studies to identify forgotten and degraded remains.
“Our goal is to make sure that it’s not just wealthy agencies that have access to this technology because we want to see every unknown deceased person given the opportunity to be identified,” he said.
Following Kwan’s arrest, police urged people to consider uploading their DNA profiles to databases that investigators can use for FIGG, including GEDmatch PRO and FamilyTreeDNA.
People can choose to upload their genetic information to these databases after using a commercial service such as 23andMe or AncestryDNA, which police generally cannot access. Around 5-10 per cent of profiles in their database are believed to be Australian.
There were privacy issues when FIGG first came to prominence. Some genealogy services automatically allowed users’ data to be used by police. The lack of transparency meant that some of the “genetic informants” used to catch the Golden State Killer did so unwittingly; They uploaded data to track down relatives and eventually identified a killer. Most databases have since moved to a more transparent opt-in system, but in Germany FIGG is still relevant largely banned due to privacy concerns.
All DNA data uploaded to GEDmatch PRO is enabled to identify human remains, but users must choose to manually enable their data to be used to find perpetrators of violent crimes.
Detective Superintendent Jayne Doherty, Commander of the NSW Police Sex Crimes Unit, said in a statement following Kwan’s arrest: “FIGG is only used for murders, sexual assaults or unidentified human remains.”
“People are considering joining; you can help us solve these serious problems.”
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Angus Dalton is science correspondent for The Sydney Morning Herald.Connect with: X or email.
