Loudoun County Turns to Composite Image Based on DNA to Crack Cold Case - NBC4 Washington

Loudoun County Turns to Composite Image Based on DNA to Crack Cold Case



    DNA Yields Composite of Cold Case Sex Assault Suspect

    Northern Virginia bureau reporter David Culver reports on a new way to take DNA and come up with a composite. (Published Wednesday, May 11, 2016)

    The composite shows a suspect with fair skin. His eyes probably aren't green, blue or black. His hair is probably brown, but there's a good chance it's reddish, too. And he probably has some freckles.

    The composite even shows what is likely to be the shape of his face, based on his northern or western European ancestry. 

    What's different about this composite is that it was not drawn from a witness' memory, but from a DNA sample left where a 9-year-old was abducted and sexually assaulted.

    It's a DNA composite, called a "Snapshot," and created by the Reston laboratory Parabon NanoLabs at the request of the Loudoun County Sheriff's office.

    "So, what Snapshot does is it reads that DNA sample that was found at a crime scene and gives the investigators some information about that person," said Dr. Ellen Greytak of Parabon Nanolabs.

    It's the first time Loudoun County has used this technology.

    The crime that Chapman's deputies are investigating is a cold case from June 1987 in Sterling. A man broke into a home on East Poplar Road early one morning, abducted a 9-year-old girl and sexually assaulted her.

    Investigators tried to find a DNA match but could not. Now, Snapshot offers them a new tool.

    Greytak would not comment on the Sterling case. But in general, she explained, the technology works by understanding how genes affect our appearance and the likelihood that certain groups of people have certain physical characteristics in common, including eye color, hair color and skin color.

    She showed an example using a Dr. Pepper bottle. Swabbing the rim of the bottle after a member of the lab team drank from it, the lab's staff began to reconstruct the profile of the drinker.

    "This person most likely has fair or very fair skin, so 87 percent confidence," Greytak said. 

    She even had guidance on facial structure: "the nose, brow and chin are sticking out more," she said.

    The technology is not a replacement for witness information or DNA matches. But when there are no other clues available, police hope the Snapshot sketch can at least narrow the field of suspects.

    "We’re excited about the technology," said Sheriff Mike Chapman of Loudoun County. "We hope that it’ll produce the results that we want it to produce."