The grisly double homicide of a South Carolina mother, Candra Alston, and her three-year-old daughter, four years ago, left few clues for investigators, and more importantly, no eyewitnesses. But police are now hoping that a computer-generated image created with DNA found at the scene might help solve this gruesome murder, and bring closure to family and loved ones.

The City of Columbia Police Department went public with a rendering of a “person-of-interest” that was created by cutting edge technology, with funding from the Department of Defense, commercially called “Snapshot.” Provided by Virginia-based Parabon Nanolabs, the picture is like an artist’s composite sketch of a suspect, only this time, the artist is the DNA genome itself.

“Traditional sequencing treats DNA as a fingerprint,” said Parabon director of bioinformatics, Dr. Ellen McRae Greytak, in an exclusive interview with Forensic Magazine. “But, we treat it like a blueprint.”

Instead of just matching DNA samples to a database, Snapshot looks at tens of thousands of DNA markers that code for the differences in appearance between people, and uses complex algorithms to compare these results with over 10,000 subjects on file. Called forensic DNA phenotyping (FDP), the system then combines this raw information to reverse engineer an image of the suspect, that police in Columbia, South Carolina are hoping will help crack the unsolved murder case.   

“This technology provides a similar service to an eyewitness,” Greytak said. “A genetic eyewitness.”

The new technology can predict genetic ancestry, eye, hair and skin color, freckling, and facial shape in individuals from any ethnic background, and even individuals with mixed ancestry. In one practice case with a “major metro police department,” the company said it determined not only the general ancestry of the person (i.e., European, East Asian, Native American etc.), but that “the individual had a Japanese father and a Latino mother.” Greytak said, the predictions are 80 percent accurate, and can exclude certain physical traits by up to 95 percent, with a margin of error of less than two percent.

“Our goal is to give investigators new ways to use DNA,” Greytak told Forensic Magazine. “Instead of just matching DNA to existing samples, we want to use the DNA to generate investigative leads.”

But some of the most telling physical features, like height and age, still remain elusive to Snapshot’s scrutiny. Greytak said these features can be extremely “complex” to predict. Still, law enforcement remains hopeful that Snapshot will shed new light on this case, and help bring the murderer of Alston, 25, and her daughter, Malaysia Boykin, to justice.

“I am pleading with the public to help…” said Ms. Alston’s father, Carl Alston, in a written statement. “It’s hard to come to grips with what happened.” Although police are not releasing the exact cause of death, there were no signs of forced entry at the home and police believe the murders appear to be of a “personal nature.”

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What’s next for Snapshot?

The new technology can predict genetic ancestry, eye, hair and skin color, freckling, and face shape in individuals from any ethnic background, and even individuals with mixed ancestry.CEO Steven Armentrout said that his company is working a number of other live investigations, but was not allowed to give further details. Most of Parabon’s clients are generally law enforcement, he said, and that the real strength of the Snapshot system isn’t incriminating one suspect, but excluding dozens of others.

“The real power is being able to exclude people from consideration,” Armentrout told Forensic Magazine. “In this way, we can save a lot time and resources.”

By employing Snapshot at the beginning of an investigation, the suspect pool can be significantly reduced leading to saved time, money and man power.

“After participating with police departments, we learned a lot about the way [law enforcement] operates, which is by exclusion,” Armentrout said. “They wanted us to eliminate as many possibilities as the technology allowed.”

He said eliminating suspects from the start, makes everything more efficient downstream. “This has the ability to really change the way DNA is used not only at the end of an investigation to ID an individual to a crime case, but as an investigative tool that moves the DNA evidence to the front of the investigation.”

But FDP has its critics, too. As of 2013, Belgium and Germany expressly forbid FDP for anything other than determining the sex of an individual, and Texas remains the only state in the US to have expressly authorized FDP testing.1 Critics say that too much genetic data, like medical information, likely habits and possible addictions, will be able to be gathered in the near future compromising personal privacy rights.

But, Greytak said that they are not using the technology for anything other than finding out what people can see with their own eyes.

“We limit our work to externally visible characteristics,” Greytak said. “Things that they know about themselves, that people would know just by looking at a person — it’s public information.”

The next advancements that are right around the corner for Snapshot are called “hair morphology” — describing whether an individual’s hair is anywhere on the spectrum of curly, wavy or straight.


Murphy, Erin.  “Legal and Ethical Issues in Forensic DNA Phenotyping.” Public Law & Legal Theory Research Paper No. 13-46. (July 2013)  NYU School of Law. Web. 15. Jan. 2015.