Cover Story, DNA Phenotyping
September-October 2019

Snapshot of a killer

By Jane Starnes
Assistant Attorney General in Austin

On the evening of May 13, 2016, 25-year-old Rhonda Chantay Blankinship (Chantay to her family and friends) went for her usual evening walk around her neighborhood in the North Lake neighborhood in rural Brown County.

As she did every evening around sunset, she called her grandfather to say she was down by the community mailboxes and was on her way home.

            But Chantay never came home. Her worried grandfather, Charlie Barnett, drove around the neighborhood looking for her. By morning, her family had called police and reported her missing. The police didn’t require the usual waiting period to file a missing person report because Chantay was intellectually disabled. She had been diagnosed with pervasive developmental disorder as a child, and although she had graduated from high school, she could not read or write more than a few words. She had a speech impediment and could not drive, hold a job, or live independently. She lived with her grandfather, boyfriend, and other family.

            She loved listening to music on her phone, shopping for clothes, eating at the local café, and walking around her neighborhood. She attended the North Lake Community Church and sang in the choir. She was pretty and very petite, standing less than 5 feet tall and weighing 89 pounds. She also had seven siblings who were very protective of her. Everybody loved Chantay. She had no enemies. When news of her disappearance spread, people from throughout the community volunteered to be part of the search party and scour the area looking for her.

            About five miles from Chantay’s neighborhood stood an old, dilapidated Victorian house on several acres of land. It was a place where high school kids met to drink and party. The house looked like the perfect scene for a horror movie, with dried, rotted wood falling away from the structure and holes in walls and the roof. Two days after Chantay’s disappearance, neighbors volunteered to search for her. Two of them, Charlie Radle and Jackie Neal, approached the abandoned property. They saw a clump of hair and a bright colored, rubber bracelet just inside the gate, and they noticed fresh tire tracks. They went inside the gate, walking through the weeds to a storm cellar a few yards from the house. Just outside the storm cellar, they saw another bright, rubber bracelet. Radle and Neal looked down inside the open storm cellar and saw Chantay, lying head-first down the concrete stairs and wearing only a T-shirt. Her head and face were covered in blood. A bloody lawnmower blade lay nearby.

            An autopsy revealed that Chantay died from blunt force trauma to her head, face, and neck, consistent with the lawnmower blade being used as the murder weapon. There was also a shoe print on her chest. The medical examiner found evidence of strangulation, and there was evidence she had been sexually assaulted. Based on semen found in Chantay’s body during the autopsy, a DNA profile was developed.

The investigation
Sgt. Scott Bird from the Brown County Sheriff’s Office, Texas Ranger Jason Shea, and many other officers from the Brown County Sheriff’s Office began the investigation. More than 100 people were interviewed. All of the registered sex offenders in the area were investigated, and several people submitted to polygraph examinations. More than 30 men consented to providing DNA samples. These samples were compared to the DNA from Chantay’s body, but no match was found.

            With the approval of the Texas Department of Public Safety, the DNA sample from Chantay’s body was entered into the CODIS system. However, the sample did not return any hits, nor did a familial search in CODIS generate any leads.

            Law enforcement couldn’t find anyone with a motive to kill Chantay. Her boyfriend had been at work at his restaurant job the night she disappeared, and he was ruled out as a suspect. Family members and multiple other people were also ruled out. Investigators even followed up on bizarre leads, no matter how far-fetched they seemed. Someone said they saw Chantay get into a stranger’s car; a woman said her boyfriend bragged about killing Chantay; another woman said her ex-husband was in an occult gang and the gang killed Chantay as part of a ritual. None of these tips led to any credible evidence.

            While the police kept working on finding Chantay’s killer, the tips became less frequent, and the case stalled for several months. On the one-year anniversary of her death, the North Lake Community Church held a service in Chantay’s memory. There was a candlelight vigil to remind people that Chantay’s killer was still on the loose. The local newspaper ran an article, reminding people of the $5,000 Crime Stoppers reward. Yet the case still remained unsolved with no further avenues for traditional investigations available.  

A new idea: DNA phenotyping
One night, a Brown County Sheriff investigator, Carlyle Gover, was watching a true crime television show that mentioned a new technique called DNA phenotyping. Gover told Sgt. Scott Bird about this technique. Bird was skeptical, but given their lack of progress on the case, he searched online and found a company that did DNA phenotyping called Parabon Nanolabs.[1] Still skeptical, Bird called Parabon Nanolabs and spoke with Dr. Steven Armentrout, the president of the company. Parabon gave Bird the names of several law enforcement agencies that had used Parabon’s services and the names of the investigators as references. Bird called these investigators and found that the agencies that had used Parabon’s services had about a 50-percent success rate. Given the lack of progress on the case, a 50-percent chance of success seemed promising.

            But a major hurdle to overcome before Bird could get the green light to send a DNA sample to Parabon was the cost. Brown County Sheriff’s Office had already spent quite a bit of money on the case, mainly on lab fees, and they just didn’t have an extra $3,600 in the budget. The sheriff told Bird that he could do it if the District Attorney’s Office would agree to pay for half the cost. When Bird first approached Brown County District Attorney Micheal Murray with the idea of sending a DNA sample to Parabon Nanolabs, Murray was also skeptical. But during a congenial discussion at TDCAA’s Annual conference, Bird convinced Murray to pay for half the phenotyping cost. Once he had permission, Bird obtained swabs from Chantay’s body from the medical examiner’s office and sent them to Parabon Nanolabs to get the process started.

About Parabon Nanolabs
Parabon Nanolabs, based out of Reston, Virginia, offers services including DNA phenotyping and genetic genealogy.[2] In this case, only DNA phenotyping services—the science of predicting which traits affect a person’s appearance—were utilized.

            DNA phenotyping uses Single-Nucleotide Polymorphism (SNP) technology to generate a digital composite drawing, or “mugshot,” of a potential suspect. The company does this using a large database of subjects from whom they have collected DNA and 3D facial scans. Traits that affect appearance are, to varying degrees, genetic—meaning they are inherited from one’s parents. We commonly observe this principle in the similarities in appearance among family members. Parabon Nanolabs has identified certain genetic markers to correspond with externally visible characteristics of a person, and that’s how the DNA phenotyping compiles all of these predictions to generate a digital “mugshot,” which Parabon calls a snapshot.

            With a sufficiently large collection of subjects, Parabon Nanolabs has developed algorithms to make statistical predictions of hair color (natural hair color, not dyed), eye color, skin tone, level of freckling, facial morphology (face shape and facial features such as the nose, mouth, and eyes), and ancestry of the person. For example, if the suspect has European ancestry, the lab can generally report the specific region of Europe his ancestors come from. The algorithms can also determine if the contributor of the sample has Hispanic, Asian, African, Middle Eastern, or Native American ancestry.

            The company can potentially generate leads in cases where there are no suspects or database (such as CODIS) hits; it may also narrow suspect lists, rule out suspects, or help solve unknown human remains cases. According to Dr. Armentrout, Parabon’s services are most appropriately used as a tip-generating tool or as an exclusion tool, and he generally discourages the use of DNA phenotyping to develop probable cause or as a basis of a search warrant. Once a tip is generated, police can focus on a possible suspect and obtain a surreptitious or consensual DNA sample from the suspect.

            The science behind DNA phenotyping has not yet been tested in court or been the subject of a Daubert[3] hearing, although Dr. Armentrout says he believes the science would withstand such a challenge, as it generally boils down to basic, well-accepted DNA science, plus statistics. It is worth noting that Parabon’s techniques have not been published in peer-review journals, nor been subjected to any external validation studies, because Parabon maintains that its methods are proprietary. However, in 2016, the University of North Texas, with funding from the National Geographic Society, conducted a blind evaluation of Parabon Snapshot, and the results were presented at the 2016 International Symposium on Human Identification. According to Dr. Bruce Budowle, executive director of the University of North Texas Center for Human Identification, the evaluation generally found the eye color, hair color, and ancestry results to be accurate. The face morphology results were not as accurate, but the evaluators also had limited data to work with. Dr. Budowle believes that the technique may be useful when traditional investigation techniques have been exhausted, and Parabon’s Snapshot may be helpful to spark interest in a cold case, either by law enforcement or the public.

            The technique has been criticized by the defense bar and civil rights groups as being “science fiction.” There are certainly valid criticisms of DNA phenotyping,[4] including that a person’s appearance is not solely a result of his or her DNA. People can dye their hair, grow a beard, use drugs, engage in lifestyle choices that affect their appearance, or lose or gain weight. However, if police are using DNA phenotyping to exclude suspects or to generate tips and then follow up with more traditional methods, there should be little or no need for a Daubert hearing about it. Police and prosecutors should be aware of the limitations and not be too quick to include or exclude a suspect based solely on a DNA phenotyping image.

            Parabon Nanolabs requires the law enforcement agency or laboratory to submit a sample of the DNA. If there is at least one nanogram of DNA remaining, the lab can use that for the analysis. Parabon will not base its analysis on a previously developed STR profile done by another lab, as it needs some actual evidence instead of reports from another lab. In this case, the Brown County Sheriff’s Office sent a swab collected from Chantay’s body to Parabon Nanolabs. It took a month from the time Sgt. Bird submitted the DNA samples to receive the report. The report generated revealed the following:

            •          the contributor of the DNA is male;
            •          he is primarily of Northern European ancestry (91.59 percent Northern European and 6.19 percent Northern Middle Eastern),
            •          his skin color is fair to very fair, with a 79.6-percent confidence associated with this finding,
            •          his eye color is blue to green (not hazel, brown, or black) with a 91.8-percent confidence associated with this finding,
            •          his hair color is brown to blond (not black), with 97.9 percent confidence, and
            •          he has few to some freckles, with 33.3 percent confidence.

The report generates a visual image based on age 25 and a body mass index of 22. The age and BMI can be adjusted if this information is known to police. Here is the image generated in our case:

Sgt. Bird posted the digital “mugshot” that Parabon Nanolabs generated on the Brown County Sheriff’s Office Facebook page. Police also showed it to Chantay’s family. One of Chantay’s brothers told police, “That looks like Ryan Riggs,” a neighbor and the brother’s former classmate. Up until that point, 21-year-old Ryan Riggs had not been on anyone’s radar. He was an acquaintance of Chantay’s boyfriend and lived in the neighborhood, but he did not have a close relationship with Chantay or her family.

            After Chantay’s brother noticed the similarity between the digital image and Ryan Riggs, police attempted to speak to Riggs, but he was nowhere to be found. His parents said they didn’t know where he was. Law enforcement tried for several days to find him, but he had apparently left town. During their investigation, deputies discovered that Riggs had illegally dumped some trash, so a warrant was obtained for a charge of illegal dumping. Deputies attempted to find Riggs to execute this warrant, but he was still not home or at work. Riggs’ parents claimed they hadn’t seen him for almost a week and a half, although he had been in the house to leave $20 and a note apologizing for missing his mother’s birthday. Six days later, Ryan Riggs re-appeared.

Riggs’s surprise confessions
On November 15, 2018, exactly 18 months after Chantay’s body was found, Riggs showed up at the North Lake Community Church accompanied by his parents. Riggs, who had been a sporadic attendee at that church, met with the pastor, Ron Keener, and confessed to Keener that he had murdered Chantay Blankinship, though he made no mention of sexually assaulting her. He told Keener that he wanted to confess to the Wednesday night church congregation “to make things right.” Keener said he would allow Riggs to address the congregation but that he would be calling Brown County Sheriff Vance Hill as soon as the service was over.

            Riggs stood up in front of the sparsely-attended congregation and confessed, “I’m a murderer. I killed Chantay Blankinship.” He gave no details, and again, made no mention of sexually assaulting her. Several members of the congregation gasped. Some came up and hugged him. Immediately after making his stunning confession at the church, Riggs went with Pastor Keener and his parents to the Brown County Sheriff’s Office. There Riggs gave a two-hour confession to Sgt. Bird and Texas Ranger Jason Shea.

            It was a weirdly calm, matter-of-fact confession, much different from a typical one because there were no denials and no back-and-forth that usually occur before a suspect finally admits his involvement. Riggs came right out of the gate with, “I’m the one who murdered Chantay Blankinship.” Riggs said he knew Chantay, just like everyone in the community knew her. He said he saw her by the community mailboxes, asked her to hang out, and took her in his truck to a lookout point by the lake. He said he talked and flirted with Chantay, then took her to a secluded area, strangled her in the front seat of his truck, took her clothes off, and raped her. He said Chantay fought him, but she couldn’t scream because his arm was pressing against her neck.

            After he raped her, and while she was unconscious but not dead yet, he took her to the abandoned Victorian house. He said he dragged her and threw her over the fence, then got a lawn mower blade out of the back of his truck and beat her on the head and face with it to make sure she was dead. Riggs said he was thinking, “I need to make sure she doesn’t wake up and tell on me.” Riggs admitted he’d also stomped on Chantay’s chest. After he left her body in the storm cellar, he took Chantay’s cell phone and threw it away several miles down the road. Riggs told police, “I wanted both things to happen, the rape and the murder.” He described “having a part of me that wants nothing but destruction and evil.” He admitted he knew Chantay had disabilities and chose her because she was small and would be “an easy target.”

            When asked why he confessed, Riggs told police he had been at home hiding when they came to serve the warrant for illegal dumping, and “I knew the cops weren’t there at the house about the trash.” He admitted that he had gone on the run after that day. He said that he had contemplated suicide and “spent time talking to God.” He claimed that God told him, “If you want salvation, this is what you need to do.’” Riggs said he went to the church “to turn myself in to God. Now I’m turning myself into the law.” When asked what punishment Riggs thought he deserved, he replied, “Death, for sure.”

            Fortunately for us prosecutors,[5] the officers had the foresight to take the interview a step further and did not stop once they got the confession. They kept Riggs talking and dug deeper into his background. He told them about his drug use, his family, and his childhood. This information was helpful later when we had to assess whether to seek the death penalty—specifically, as we looked for evidence to prove future dangerousness and any mitigating evidence. Riggs admitted to using and selling methamphetamine frequently, but said he was not high the day of the crime. He said that he’d made a half-hearted attempt at suicide before, that on numerous occasions he’d tried to drown his pet chihuahua in a five-gallon bucket of water, that there was a family history of mental illness, and he hinted at some sexual abuse by a relative.

            Riggs admitted to attending Chantay’s funeral and participating in the search party. It was evident from the interview that Riggs was articulate, literate, and coherent. While his confession was unusual, he was not exhibiting any active symptoms of mental illness. He was able to define rape as “non-consensual sex, sex against your will,” and understand other legal concepts. He consented to the police taking a buccal swab for a DNA sample. Lab tests confirmed that his DNA was a match to the semen found in Chantay’s body.

Whether to seek death
The State issued subpoenas for Riggs’s school records, juvenile criminal records, medical records, and mental health records. We determined early on that when he was 16, Riggs broke into a house and stole a gun, allegedly because he was suicidal due to problems with a girlfriend. After he made threats that he wanted to kill himself with the stolen gun, he was hospitalized in a psychiatric facility for a few days. He was diagnosed with depression, but there was no diagnosis of any kind of psychotic disorder. He had some brief follow-up treatment with a counselor, but there was no further documentation of mental illness.

            Riggs had a couple of other run-ins with the law as a juvenile and some minor discipline problems at school, but nothing major. We could tell, as the case progressed, that the only defense his lawyers might raise at guilt-innocence would be insanity, but more likely, the defense would concede his guilt and spend all its time trying to disprove future dangerousness and prove mitigation to save Riggs from a death sentence. Of course, the wild card in the case was how a jury would react to Riggs’s confession at the church and whether jurors would view this acceptance of culpability and display of remorse as mitigating.

Deposition of an elderly witness
Chantay had lived most of her life with her grandfather, Charlie Barnett. At the time of Chantay’s death, Mr. Barnett was 87 years old. He was a sharp, witty, and somewhat crusty old guy who had been a Navy diver and a police officer for many years. He seemed to be in relatively good health, and even though he was officially retired, he still worked at night operating a street cleaning machine for his brother-in-law’s company. He said he was planning on living to 110 years old.

            But, as I explained to him, the law[6] allows us to take a deposition of a witness over 65 years of age, and even though he was currently in seemingly good health, a deposition was an insurance policy in the event something happened to him before trial. At a jury trial, we would need Mr. Barnett to introduce the jury to Chantay, describe her disabilities, and give us the timeline of the night of her disappearance. Mr. Barnett agreed that a deposition would be a good idea.

            We filed a motion to take his deposition, and the defense agreed to it. We set a date, scheduled a court reporter and videographer, and reserved a courtroom. Mr. Barnett’s deposition went off without a hitch, although he told us afterward that it rattled him to his core to sit in the same room with “that son-of-a-bitch,” Riggs.

            As it turned out, it was a good thing we did this deposition, because a few months later, Mr. Barnett had a stroke. The stress of losing Chantay and learning the horrible details of her death had clearly taken a toll on him.

The guilty plea
As the case progressed, we had pretrial hearings, and a trial date was set for September 2019. At one of our meetings with Riggs’s attorneys, the defense team made it clear that Riggs would be willing to plead guilty to capital murder if the State waived the death penalty. Defense counsel gave us a preview of its punishment case, including some of the mitigation evidence. And as usual in a capital case, counsel also brought up the costs to the county that would be incurred in expert fees, mental health evaluations, and brain scans.

            After meeting with Chantay’s family and discussing this plea option, the family agreed that the State should allow Riggs to plead guilty and be sentenced to life without parole. After almost three years of grief, the family wanted closure. They wanted the certainty of a plea and waiver of appeal, and they didn’t want to endure a trial and years of appeals.

            On February 15, 2019, Ryan Riggs admitted his guilt in court, pleaded guilty to the capital murder of Rhonda Chantay Blankinship, and was sentenced to life without parole. Chantay’s whole family, including Mr. Barnett, was in attendance. Her mother, Michelle McDaniel, gave an emotional victim impact statement, and there wasn’t a dry eye in the courtroom. Mrs. McDaniel told Riggs, “You will never get married. You will never have grandkids for your mom and dad. My daughter would have forgiven you because that’s the way she was. I hope one day you’ll realize everything you’ve done, not only to us, but to your family.”

            By the end of the day, her family had posted online a photo of Chantay, sitting by the lake playing with her phone, with the caption, “I got my justice.”



[2] Genetic genealogy mines data from public databases such as to look for the suspect’s DNA or a relative of the suspect. Parabon has made this service available since May 2018, but it was not available when the Riggs sample was submitted.

[3] Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993), the U.S. Supreme Court case outlining the standard for admitting scientific evidence and expert opinions in court. The Texas standard for the admission of “hard sciences” is Kelly v. State, 824 SW2d 568 (Tex. Crim. App. 1992).

[4] Here are some articles critical of DNA phenotyping: Curtis, Caitlin, & James Hereward, “How Accurately Can Scientists Reconstruct a Person’s Face From DNA?”, The Conversation, May 4, 2018.; and Stanley, Jay. “Forensic DNA Phenotyping,” ACLU Speech, Privacy and Technology Project, November 29, 2016.

[5] The Brown County District Attorney’s Office requested the assistance of the Office of the Attorney General on this complex case, and Ms. Starnes was appointed as a special prosecutor. District Attorney Micheal Murray and Assistant District Attorney Elisha Bird were also prosecutors on the case.

[6] Tex. Code of Crim. Proc. Art. 39.025.