SEATTLE — It’s been almost 30 years since the body of 16-year-old Sarah Yarborough was found strangled in Federal Way.
Her killer has never been found.
But a suspect profile using brand-new DNA technology is breathing fresh life into the cold-case. Yarborough’s case is just one of dozens the company – Parabon Snapshot – is trying to solve around the world, said Dr. Ellen Greytak, the director of bioinformatics with the company.
“We absolutely think this is revolutionary,” Greytak said. “We’ve seen a number of cold cases and helped recent investigations be more efficient.”
How the new DNA Snapshot technology works is complicated. To start, investigators gather DNA found at a crime scene. The DNA is analysed, and hereditary markers predictable through DNA – such as hair color, freckling, shape of face, genetic ancestry and skin color – are categorized by likelihood. Parabon Snapshots then reverse engineers the DNA into a physical profile.
What the sketch becomes is a kind-of best guess as to what someone will look like.
Parabon Snapshots can also narrow down what someone doesn’t have. For instance, Snapshot Phenotyping can say that there’s a 85 percent chance the suspect has blue eyes, 95 percent chance they have either blue or green and a 99.9 percent chance they don’t have brown eyes.
That way, law enforcement investigators can focus away from people with brown eyes.
It’s not the end-all-be-all. Instead, DNA Phenotyping is more of a tool in a toolbox for investigators. Greytak said.
“It’s to help figure out who you shouldn’t be looking for,” Greytak said.
The company has been used by law enforcement groups since late 2014. They’re mostly brought in for cold-cases, Greytak said, as a way to jump-start a stalled case. Perhaps the DNA Snapshot offers a suspect profile different than originally thought, opening up more potential suspects.
The profile can’t predict height or weight. But used in tandem with, say, a grainy surveillance video, it adds an extra element.
More than 150 have all over the world have used the program. Along with crimes, it helps in missing remains cases, where the physical profile of the remains is so degraded they can’t accurately compose a victim sketch.
Will the new technology help solve all crimes? No.
But it’s another avenue to turn to in helping bring loved ones closer to a solution.
“We’re providing a genetic witness,” Greytak said.