Sierra Bouzigard was 19 years old when she was murdered and left beaten beyond recognition by the side of a road in Lake Charles, Louisiana. Before she died, she fought back, scratching her attacker and leaving bits of skin containing her killer’s DNA underneath her fingernails.
Police are looking for the killer using that scrap of genetic material—but not the way you might think. In this case, the killer’s DNA didn’t match any suspects or criminal database, so scientists are using the DNA to assemble a high-tech version of a tried-and-true investigative tool: a sketch of the killer’s face.
(Read more in “How Science Is Putting a New Face on Crime Solving” in the July issue of National Geographic.)
The technology is called DNA phenotyping, and so far it can produce only a rough approximation based on genetic factors such as geographic ancestry, eye color, and the shapes of facial features.
Academic scientists including Mark Shriver, an anthropologist at Pennsylvania State University, pioneered DNA phenotyping, and today a company called Parabon NanoLabs is developing a tool for forensic use, called Snapshot. Parabon emphasizes that police would never rely upon a DNA-based image alone to identify a suspect, but that detective work combined with a suspect’s DNA can effectively narrow down the pool of suspects.
How hard is this to do? See for yourself. National Geographic worked with Parabon to develop a quiz using the DNA phenotype of Max Aguilera-Hellweg, the photographer for the July magazine feature on forensics. Parabon reverse-engineered Max’s face using his DNA profile, as the hypothetical “suspect” or target. Other National Geographic photographers stand in for the lineup along with a photo of the real Max.
So, can you identify Max from the photos below? Technically, no—DNA phenotypes are not accurate enough to make a positive identification. But they can be used to eliminate suspects whose genetic profile clearly differs from the one gleaned from DNA left at the crime scene.
So the proper forensic question is: Can you identify who is NOT Max?