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The reconstruction of faces using DNA, called phenotyping, is being used in criminal investigations nationwide. The technology has been used in dozens of cases in the U.S., including one double-homicide case in South Carolina where police released a computer-generated image of a person of interest—probably the first of its kind.
But the facial images constructed from DNA samples are all defaults. They can only produce an image based on a standard expression of the DNA: a person at age 25, and with a body mass index (BMI) of 22. If the suspect is significantly older or heavier, younger or skinnier, or even with tell-tale facial scarring, the image may not resemble the actual appearance.
Now a company is employing the touch of a forensic artist to help produce more-accurate visualizations of persons unknown, in concert with the computerizations.
“You’re talking about a more-focused image for people to look at,” said Thom Shaw, of Parabon Nanolabs, a veteran forensic artist from Northern Virginia. “We found things I could add which would help in making a truer image.”
Parabon can produce faces based on the gender, race, and other features based on the genetic information alone. Most often, this has proven effective for “ghost” offenders – unknown suspects who leave blood, semen or saliva at the scene – but whose information does not produce a “hit” in various databases.
The computer-visualized faces provide lead helping investigators prioritize their list of suspects – by honing in on certain groups that may match the scientific data available at the scene.
But characteristics not dictated by genetics can make all the difference to recognizing a person of interest. Age and BMI, facial hair, baldness, glasses, scars, piercings and other nuances can make a huge difference in those investigative leads – and the genetic information could not provide those.
This is where Shaw comes in.
As a law-enforcement officer of 29 years in Northern Virginia, Shaw has been a forensic artist for 21 years – and even has training in reconstructing faces from skulls.
Shaw can take a genetic profile, and based on the investigation, make the suspect fatter, older, with a beard or with glasses. Those details can make a huge difference in an officer searching a street – or to a witness who may only recall a certain few key details of an appearance.
“In situations where investigators have descriptive information about a subject that is not encoded in DNA, such as an estimate for age or information indicating a subject has facial hair, Thom can expertly enhance [an image],” added Ellen Greytak, also with the Parabon company.
Dr. Steven Armentrout, the Parabon CEO, said that the new software, complete with forensic imaging, can add new information to the images. “Age and BMI alone can dramatically affect the appearance,” Armentrout told Forensic. “It’s a really nice blend of science and art.”
The genetic information also can help the other way – with adding touches that would not be available from severely-decomposed remains, Shaw said.
“Usually forensic artists leave out information like eye color and skin tone,” he said. “The DNA can determine those aspects.”
The caseload for the technology is in dozens, but will soon approach 100, according to Armentrout. Although the company could not speak about several pending investigations, updates are expected in the coming months.