A recent arrest made in a 30-year-old murder is an absolute “game-changer”—it is the first case using whole genome sequencing to separate mixtures. (Parabon NanoLabs researchers achieved successful separation of mixtures using microarray genotyping in 2015 and demonstrated its successful use for genetic genealogy in summer 2018.)
On Dec. 20, 1987, Cleveland police responded to a report of a deceased female in a wooded area. Seventeen-year-old Barbara Blatnik was found nude and strangled to death 30 minutes away from her home. At the time, DNA was found beneath Blatnik’s fingernails, but it was a mixture of hers and her killer’s. DNA techniques in 1987 couldn’t do anything with a female and male DNA mixture, so the case went cold. Until Porchlight Project and Colleen Fitzpatrick’s Identifinders International stepped in.
Using whole genome sequencing, Fitzpatrick and her team sequenced the DNA mixture, then subtracted out the sequence created from the DNA of the victim. The result was a sequence for the suspect, which they ran through Identifinders’ bioinformatics pipeline to create autosomal SNP data for just the suspect. Fitzpatrick uploaded that data to GEDmatch, worked the genealogy and received a match for 67-year-old James Zastawnik, who police promptly arrested for murder.
“Using CODIS, is it very difficult to separate mixtures without a clear major and minor contributor. That is the main reason the case went unsolved for so long,” Fitzpatrick told Forensic. “Demonstrating it's possible to separate mixtures using whole genome sequencing and genetic genealogy is a game-changer. It opens the door for so many other sexual assault cases that otherwise may never be solved.”
The Porchlight Project is a nonprofit that provides assistance to families of the missing and murdered in Ohio. It was founded by investigative journalist and author James Renner, who has written about Fitzpatrick and her genealogy magic in the past. Blatnik’s case was the first for The Porchlight Project—and it turned out to be a success.
“I want to express an immense amount of gratitude to everyone at The Porchlight Project for the funding that they provided to help get the needed DNA testing that was done to close this case. They have done an incredible service to the Blatnik family and our police department,” said Cuyahoga Falls Mayor Don Walters.
The Porchlight Project intends to take on three to four cases a year, providing free private investigative services, funding for DNA testing and media support. Fitzpatrick said she and Renner are already considering which new cases would be best to collaborate on next.
“We hope to see many other sexual assault cases coming in that have mixtures that have defied resolution,” Fitzpatrick said. “We would like to test the limits of our mixture separation techniques in terms of percent mixture and the quantity and quality of DNA available. We want to extend the applicability of genetic genealogy to more and more challenging cases that, even given the availability of genetic genealogy, are currently considered and unsolvable.”
Photo: James Zastawnik was arrested and charged with the murder of Barbara Blatnik 30 years ago. Credit: Cuyahoga Falls