1 Fighting Crime With Science

As a teenager, Dr. Susan Walsh loved the TV show “The X-Files.” She was particularly drawn to the character of Dana Scully, a hyper-rational doctor-cum-FBI agent who brought a scientist’s skepticism to investigations of paranormal phenomena and deployed her medical training to determine cause of death for the show’s victims.

The fact that Scully used science to solve problems and pursue justice intrigued Walsh. She wanted to explore a career in forensics but was on the fence about how to do it. Should she go into law enforcement? Become a scientist? The show helped her to decide. She loved the science. “It did start with Scully, if I’m being honest,” she said.

Walsh studied biochemistry and, while working on her master’s degree in DNA profiling, she happened onto a research paper that caught her attention. Australian scientists had found DNA markers corresponding to eye color, and Walsh began to wonder whether those techniques could be applied to criminal investigations. If crime-scene DNA could be analyzed for markers that relate to physical appearance, Walsh suspected that could help investigators identify suspects — and take crime fighting to a new level.

“Oh wow, that’s so cool that we’ll one day be able to predict what people look like,” using DNA, she thought. “In an application of a forensic setting, that’s amazing.”

That was 2005. Today, Walsh is at the top of her field. An assistant professor in the School of Science at Indiana University Indianapolis, she runs a lab researching what is now known as forensic DNA phenotyping, or FDP. Walsh has worked on locating genes related to eye, hair, and skin color and has built an open-source tool for people, including in law enforcement, who want to use DNA to predict those traits. She has also investigated connections between DNA markers and the appearance of various facial features, known as facial morphology.

Through her research, she came to learn that FDP works as she imagined it could: An unknown DNA sample can be parsed for genetic markers related to various traits, like hair or eye color, offering criminal investigators a glimpse into what the owner of the DNA might look like. That, in turn, could be useful information for prioritizing suspects to investigate. If the DNA says a person is likely to have red hair, for example, detectives could bump redheads to the top of their suspect list.

Still, Walsh remains cautious about how she describes what DNA can and cannot tell us about what a person might look like. At present, the idea that DNA can be used to predict facial structure — for example, what a person’s chin might look like — is more science fiction, like her beloved “X-Files,” and less science fact. The human face is a complicated structure defined by both nature (so, DNA) and nurture (like, if you’ve had your nose broken). Like others in her field, Walsh is unsure that research into morphology will ever bear reliable fruit. “We can’t even do a nose right now,” she said.

Walsh is adamant: It’s scientifically premature to deploy these methods to predict a person’s face, especially when their life and liberty is at stake. Not everyone in the field has been as chary.

“The Science Isn’t There”

A private company based in Reston, Virginia, Parabon NanoLabs was founded in 2008 with the mission of creating “breakthrough products” using DNA, with an initial focus on developing cancer therapies. It has since evolved into a prominent purveyor of forensic products, including DNA phenotyping, to police agencies. Though it’s well known among forensic scientists, it maintains a fairly low public profile and publishes few details about its operation online.

According to Parabon, its Snapshot FDP System “accurately” predicts not only eye, hair, and skin color, but also face shape. For a fee, the company will provide law enforcement agencies with a rendering of its predictions in the form of a color composite sketch, along with a “corresponding measure of confidence” in the predicted traits. The company says it has worked with hundreds of police agencies in the nine years it’s been doing this work.

As Parabon’s foothold in the world of forensics deepened, so did the concern among scientists and legal experts, who warn that the company’s sketches are, at best, misleading. Leading experts agree the science has not evolved enough to accurately and reliably provide the kind of singular image Parabon produces for police investigations. Even a scientist who helped develop the technology says it’s not ready for real-world use.

Parabon’s methodology for generating its phenotype predictions is a closely guarded secret; its system has not faced independent scientific verification and validation — the gold standard among scientists for vetting the efficacy of computer-based programs — nor has it been peer reviewed. Still, Parabon insists that its phenotyping work is based on good science. While it acknowledges that its program has not gone through traditional scientific review processes, it says the proof of Snapshot’s ability and value is in the number of law enforcement agencies that use it and say it has helped them solve cases.

Selling these singular images to police is “detrimental to the field and something we need to stop.”

For years, Walsh privately pressed the company to explain its work and grew frustrated by Parabon’s refusal to engage with her questions. Her concerns were not just hypothetical: In a criminal legal system rife with wrongful convictions and racial bias, there are countless ways using an unproven tool to solve crimes can, and does, go wrong.

Those frustrations came to a head during a March 2024 workshop at the National Academy of Sciences covering the good and bad of several next-generation forensic tools used by law enforcement, where Walsh and others sharply criticized Parabon. Selling these singular images to police is “detrimental to the field and something we need to stop,” Walsh said.

Police pay hundreds per case for appearance prediction, yet “how these tools function remains shrouded in secrecy,” noted Rebecca Brown, the former policy director for the Innocence Project and the founder of Maat Strategies, a criminal legal policy consulting firm. Speaking at the workshop, Brown cautioned against the use of FDP and other novel disciplines absent robust validation and regulation. There are “too many examples of investigative tools that become runaway trains,” she said.

Parabon’s FDP service follows a predictable pattern in forensic science: Novel techniques are developed, often by private industry, and pressed into service for law enforcement purposes before their limitations have been fully assessed and addressed.

As with other forensic innovations, like forensic genetic genealogy or facial recognition, FDP is sold as an “investigative tool” — that is, a product not intended for use as evidence in a criminal proceeding, but as a behind-the-scenes aide to police searching for perpetrators. But selling a scientifically questionable product as a mere investigative tool can have real-world consequences.

For FDP in particular, experts warn that the composite images can reinforce racial stereotypes, encourage the over-surveillance of marginalized communities, and deny criminal defendants important information about how they became a target of an investigation, which raises serious implications for Fourth Amendment privacy rights. Composites like those Parabon sells could also inadvertently taint the memories of eyewitnesses to a crime, risking potentially valuable evidence.

Paula Armentrout, Parabon’s co-founder, provided written responses to questions from The Intercept about the company’s Snapshot program. In part, the company said that The Intercept “should not quote any of the presenters” at the NAS workshop, who it claims “made many false, uninformed, and misleading statements that were not based on evidence or facts, but on misinformation propagated by inaccurate media articles, hearsay, and their own personal and political agendas.”

Walsh insists her criticisms are motivated solely by her fidelity to the science and to ensuring the transparency and accuracy of forensic tools used in the criminal legal system. To that end, she was emphatic during the workshop: Law enforcement should not be allowed to purchase phenotyping composites. “The science isn’t there. We shouldn’t be doing it,” she said. At this juncture, she said, those sketches are about as scientific as “my son drawing them.”

2 Marketing a DNA Blueprint

Parabon’s foray into forensics began in 2009, when the company secured the first of several contracts with the Pentagon’s Defense Threat Reduction Agency, which was looking for a way to identify individuals in combat zones responsible for building improvised explosive devices. Parabon proposed extracting physical traits from DNA collected from the weapons to get the job done, and a subsequent 2012 contract led to the development of the Snapshot system. “Traditional DNA analysis treats DNA like a fingerprint, useful for identification,” Parabon co-founder and CEO Steven Armentrout told the military’s Success Stories publication in 2022. “But Snapshot treats it like a blueprint for how to build a human.”

The company began marketing the service to police agencies in 2015, an effort that has been “extremely successful,” Ellen McRae Greytak, the company’s director of bioinformatics, said during a webinar for a military organization in 2020. In her presentation, Greytak briefly outlined Parabon’s work to create Snapshot: how researchers collected existing DNA information for individuals across the world to home in not only on markers for hair, skin and eye color, but also for specific geographic ancestry information; how they used machine learning to create the algorithm that generates predictions; and how, at the time, the company was developing a phone app to help gather three-dimensional images of faces to aid its morphology work. 

Once the software makes a phenotype prediction, a forensic artist steps in to shade the composite. Of course, the process has its limitations, Greytak acknowledged. It can’t predict hairstyle, for example, or any other form of non-genetic modification — like scarring, tattoos, or dyed hair — and it can’t discern a person’s weight. Parabon’s composites are developed for what a person would look like as “a young adult at a normal body weight,” she said, which the company defines as a body mass index of 22.

Parabon had already worked on “hundreds of cases,” Greytak said during the webinar, sharing a couple of alleged success stories. In 2016, Massachusetts police investigating the 24-year-old cold-case murder of Lisa Ziegert used crime-scene DNA to obtain a Parabon sketch of her possible murderer.

Detectives used the composite information to narrow down the pool of “thousands” of people who, over the years, had been noted in the case file, Greytak said. There “were maybe five guys who closely matched the predictions we made,” she said, so the cops went knocking on their doors. Gary Schara wasn’t home when the police arrived at his place, so they told Schara’s roommate to pass on the message that “we’d like to speak to him,” Greytak explained. “When Gary hears that, he flees.” Police were eventually able to track Schara down and to match his DNA to the crime, she said, prompting him to confess. “They were finally able to close this homicide case.”

According to news reports, Schara was more than just a note in the case file. In fact, he had long been a suspect: His wife gave him up to police in 1993, and he was subsequently interviewed multiple times by investigators, including from the FBI.

After police received the Parabon phenotyping report and returned once again, talking to his roommate, Schara penned a confession and tried to kill himself. Police found him the next day in a Connecticut hospital. Schara ultimately pleaded guilty and was sentenced to life in prison.

It is unclear why detectives were unable to close the case years earlier. The Hampden district attorney’s office did not respond to The Intercept’s requests for comment, but in 2019, MassLive reported that District Attorney Anthony Gulluni said the “embrace of new technology” had helped to solve the case. Still, it appears the most Parabon can claim credit for is reminding cops of at least one of their top suspects.