New Technique Separates Mixed DNA Evidence to Tell Suspects from Victims
by Dale Chappell
When 17-year-old Barbara Blatnik was found dead in December 1987, Cleveland police found DNA under her fingernails, but it was a mixture of hers and her killer’s. At the time, DNA techniques couldn’t separate mixed DNA, and the case went cold.
However, a new technique used by Identifiers International separated the DNA in the mixture and then excluded the DNA from Blatnik. The result was a DNA sequence of the suspect. But who?
Porchlight Project, a nonprofit that helps families of the missing and murdered in Ohio, teamed up with Identifiers International to get that answer. “Using CODIS, [it’s] very difficult to separate mixtures with a clear major and minor contributor” of DNA, Colleen Fitzpatrick, Identifiers International’s founder, said. Using today’s genealogy techniques is a “game-changer,” she proclaimed. “It opens the door for so many other sexual assault cases that otherwise may never be solved.”
Fitzpatrick uploaded the suspect’s DNA data to GEDmatch and got a match for James Zastawnik. He was then arrested for Blatnik’s murder. This was the first case for Porchlight Project, and it was a success.
“They have done an incredible service to the Blatnik family and our police department,” Cuyahoga Falls Mayor Don Walters said. Porchlight Project intends to take three or four cases a year. They provide free private investigation services, funding for DNA testing, and media support.
“We hope to see many other sexual assault cases coming in that have mixtures that have defied resolution,” Fitzpatrick said. “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.”