After her oldest daughter was killed last year, Michelle McDaniel and her family isolated themselves in their small Texas town out of fear that the unknown killer could be standing in line with them at the grocery store or passing them on the street. Last month, Brown County sheriff’s investigators sent McDaniel a sketch of the man they suspected in her daughter’s death, despite having no witnesses. The sketch was created using DNA found at the crime scene; a private lab used the sample to predict the shape of the killer’s face, his skin tone, eye color and hair color, the Associated Press reports. Within a week, the sheriff’s office had a suspect in custody.
For McDaniel, the DNA sketch technology known as phenotyping was an answered prayer. For police officers, it’s a relatively new tool that can generate leads in cold cases or narrow a suspect pool. For some ethicists and lawyers, it’s an untested practice that if used incorrectly could lead to racial profiling or ensnaring innocent people as suspects. Several private companies offer phenotyping services to law enforcement to create sketches of suspects or victims when decomposed remains are found. The process looks for markers inside of a DNA sample known to be linked to certain traits. Police in at least 22 states have released suspect sketches generated through phenotyping. It works like this: Companies have created a predictive formula using the DNA of volunteers who also took a physical traits survey or had their face scanned by recognition software. That model is used to search the DNA samples for specific markers and rate the likelihood that certain characteristics exist.