It's been more than twenty years since three members of the Bennett family — father Bruce, mother Debra and seven-year-old daughter Melissa — were brutally murdered. But the Aurora Police Department hasn't given up on finding their killer.
The department has employed age-progressed DNA phenotyping, a technique developed by Parabon NanoLabs and dubbed Snapshot that creates composite images of suspects from unknown DNA found at crime scenes. The result when it comes to the Bennetts is a pair of images — one offering a likeness of a possible suspect as he looked at the time of the slaying, a second aged to approximate his appearance today — that are on view below. And Ellen Greytak, Parabon's director of bioinformatics, says a growing number of other police agencies are using Snapshot, too.
"So far, we've done more than sixty different cases, and we've also done evaluations at the local, state, federal and international levels," Greytak says. She adds that "we've had one conviction and a few other arrests" in incidents whose investigations featured Snapshot, and while none of the police agencies in question has gone public with the technology's role in the cases thus far, she teases that an announcement about a success is pending.
Could Snapshot help break an even more famous cold case — the 1996 murder of JonBenét Ramsey? After all, unidentified male DNA was found on the six-year-old's underwear, providing the sort of clue that has thus far confounded investigators.
While not specifically discussing the Ramsey case, Greytak sketches out a rationale for turning to Snapshot that sounds as if it could apply to that slaying.
"Snapshot is typically used in cases were there are no witnesses, and these detectives are having to live with the fact that any person could be the perpetrator and they have no information about which suspects they should look into," she says. "The composite isn't intended to be like a driver's license photo, but it will bear a resemblance. And if you have a list of 1,000 people who were nearby that day, you can put the ones that match the most at the top, and the ones that match the least at the bottom."
Any progress in the Bennett inquiry would be welcome given the passage of time and the brutality of the act.
On January 15, 1984, according to an account highlighted on the Families of Homicide Victims and Missing Persons website and shared in our 2013 roundup of ten unsolved Colorado murders, Bruce, a Navy veteran then working at a family owned furniture store, celebrated Melissa's upcoming eighth birthday along with her, wife Debra and youngest daughter Vanessa, age three.
That night, probably between the hours of midnight and 6 a.m., the account continues, an intruder or intruders broke into the home in what homicide detective Marvin Brandt termed a "blitz attack for no reason" in which the main weapon was a hammer. Bruce met an intruder on the stairs of the home and fought valiantly; he ended up with what are described as "deep gashes on his arms and body," with his blood "splattered and smeared up and down the staircase." The killer then sexually assaulted and killed Debra and Melissa, the narrative states, and while Vanessa survived, her jaw was crushed, necessitating multiple operations on her face and head.
Although more than 500 people were questioned during the investigation that followed, no one was ever charged. But DNA was recovered, and in 2010, the Aurora and Lakewood police departments jointly announced that it matched evidence related to another unsolved homicide — the killing of Patricia Louise Smith days before the Bennetts were murdered. This discovery raised the possibility that the same person had committed both crimes.
Six years later, no one has been charged in either case. Enter Snapshot, which Greytak describes like so.
"The long and the short of it is, we predict what someone looks like just from a DNA sample," she says. "Typically, if you have a DNA sample, you enter it into a database and you search for matches. But while that's great if you have a suspect you've identified, if that person isn't in the database, you don't have a suspect. So instead of looking at DNA like a fingerprint, we look at it like a blueprint — the information that builds that person."
The technology allows Parabon to "tease out the parts of the DNA for different characteristics: eye color, hair color, the shape of the face," Greytak goes on. "The techniques that underlie it aren't that new. They've been used in the medical field for a long time, and they're known to work. But the application for appearance and forensics purposes is new."
When asked how Parabon tested the results, she offers the following example. "Let's say we've built a predictive model for eye color. We test that model on thousands of people whose eye color we know. From that, we have precise measurements of how accurate that model is for eye color. So when we make a prediction for a new suspect whose eye color we don't know, we know how confident we can be in that prediction. If we have a prediction of a blue-eyed person, that prediction will be within a certain range — and if it's in that range, we can be confident that person has blue eyes."
Granted, DNA doesn't reveal everything about a given individual — including how old he or she is when a sample is left behind.
"Age is not written into the DNA sequence," Greytak confirms. "That's why all of our composites come out at an age of 25 and a normal body weight. If the case is old, or a witness can say that person was older or heavier, we can make adjustments. But in the absence of that information, we do a default age 25 and normal body weight. And the same is true of hair styles. We can predict the color, not the style, so we put on a standard hair style."
As Greytak acknowledges, such factors "can really affect how someone looks. If that person is 300 pounds, he's going to look very different from someone who weighs a lot less. So the composite is a guide, not the exact appearance of a person."
Even so, investigators "get really excited when they hear about this technology," Greytak goes on. "Snapshot was recently featured in a National Geographic cover story, and after that, there was a new flurry of interest. Sometimes people will send us DNA samples from someone they know but we don't know anything about and ask us to do a blind evaluation. We'll make predictions, and afterward, they can see how well the technology worked. And then they'll have us use it on a cold case, and when we report back to the detectives, they'll say things like, 'Wow, I had no idea that's who we should have been looking for. I've interviewed all these people who didn't match this sample. If I'd just done this ahead of time, I could have used my time more efficiently.' And the technology also works for unidentified remains. Even if you have a skull, you don't know a person's eye color or hair color or some information about ancestry. But by blending our predictions with traditional reconstruction, it can really bring that person's appearance back to life, so we can identify them."
Below, see the aged composite based on DNA found at the Bennett family crime scene. If you have any information about the case, you're encouraged to contact Agent Steve Conner with the Aurora Police Department homicide unit cold case squad at 303-739-6190 or e-mail firstname.lastname@example.org.