DNA Doesn’t Lie: Catching the Green River Killer
By Kevin Ritchart
One man. Two decades. More than 70 murders.
Gary Ridgway, who was dubbed the Green River Killer based on the location where he disposed of his first few victims, is widely considered to be the most prolific serial killer in U.S. history.
Ridgway confessed to 71 murders that took place in Washington state from 1982 through 2001 and was convicted for 49 of them.
In May 2019, the Carlsbad, CA, office of Thermo Fisher Scientific hosted a town hall where Dave Reichert, formerly of the King County Sheriff’s Department, spoke about his time on the Green River Killer Task Force and the role DNA (deoxyribonucleic acid) played in apprehending Ridgway after many years of investigation.
“When Dave came up, people were on the edge of their seats,” said Rosy Lee, Vice President and General Manager for the Human Identification business within the Genetic Sciences Division. “The process (Dave) had to go through, this was a 20-year case for him. We owe (law enforcement) so much because these events really haunt them. The names, the faces, the families…they do not let things go.”
A few years after closing the case, Reichert wrote a book detailing his experiences with the case called Chasing the Devil: My Twenty-Year Quest to Capture the Green River Killer.
The Science Behind the Scenes
As the products and methods employed in the field of DNA forensics continue to advance, law enforcement agencies are more readily able to focus on suspects based on the evidence recovered at crime scenes.
“Forensic science has evolved,” said Sheri Olson, Director of Global Market Development, Forensics & Human Identification. “The technology is more advanced. The process of using DNA to match people is much more discriminating.”
In the early 2000s, the state-of-the-art products on the market for DNA analysis and PCR (polymerase chain reaction) amplification were part of what’s now the Applied Biosystems™ AmpFLSTR™ ProFiler™ Plus line. In recent years, these products (and others like them) have evolved to identify more genetic markers than their predecessors.
Among the Applied Biosystems™ AmpFLSTR™ products on the market today are the Identifiler™ PCR Amplification Kit, which can zero in on 16 markers, and the Globalfiler™ PCR Amplification Kit, which has the ability to match 24 markers. The markers provide the gender of a subject as well as other DNA characteristics that form a person’s genetic signature.
In the case of the Green River Killer, evidence testing revealed that the same genetic signature was present at every crime scene. This eventually led the task force to a Ridgway relative and later to Ridgway himself, who later confessed to the murders of dozens of women.
Forensics Is a Family
This Applied Biosystems line is touted as the most discriminating and widely used selection of short tandem repeat (STR) products on the market today. And the fact that they’re used daily to help victims and their families get answers following such tragic events is not lost on the people who create these products.
“Everyone involved with the products we sell understands the significance,” Lee said. “It just shows how committed people are and that they understand the consequences of what they’re doing. They’re going the extra mile to save a life and bring closure to a family.”
And while it’s the mission of Thermo Fisher Scientific to make the world healthier, cleaner, and safer, the impact is felt on a much broader scale.
“The field of DNA and forensics is a family,” Lee said. “Some of our customers and vendors have been working together for decades. We work in the academic and forensic industries with our competitors. Everyone is interested in collaborating. People are always willing to get on the phone or get on a plane to help out. As employees, we’re all part of that ecosystem.”
Olson agrees.
“The power of technology and the actual applications truly make a difference,” Olson said. “Our products are truly making a difference and making a social impact, and we’re bringing that message to other parts of Thermo Fisher Scientific.
“Every day we’re out there. We talk to customers. We collaborate with key scientists. When you hear their stories, it’s very powerful.”
Learn more about the timeline of the Green River Killer case and milestones in forensic science that occurred along the way.