- The Cautionary
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- Learning AI #31
In December 1992, a 25-year-old teacher named Christy Mirack was found murdered in her townhouse in Lancaster, Pennsylvania. Detectives collected DNA from the scene. It didn't match anyone in any database, and for 26 years, that was the end of it.
In 2017, Parabon NanoLabs took a crack at the DNA sample. They ran it through machine learning models trained to predict physical traits like eye color, hair color, skin tone, freckling, and the shape of a face, learned from thousands of people whose DNA and photos were both on file. Parabon built a face for a sample nobody could put a name to. Police released the composite to the public in October 2017. It generated no leads.
More than a year later, Parabon came back with a different service: genetic genealogy, a separate technique from the composite face. A Parabon genealogist uploaded the same DNA profile to public genealogy and ancestry databases and started mapping any hits from any person whose DNA resembled the sample.
A family tree was built around the the DNA sample from the unknown assailant.
Sifting through the tree, a match was found and traced to a man named Raymond Rowe, who was a wedding DJ and went by "DJ Freez." He was 24 at the time of the murder and lived four miles from Christy Mirack.
Scientists started matching anybody with similar DNA to the unknowns sample, until they found somebody who lived four miles away from the crime scene.
Rowe wasn't arrested off that lead alone. Undercover officers followed him to a school event, picked up a water bottle and a piece of chewing gum he'd thrown away, and sent them to a lab. Just like the detectives on TV.
The DNA matched and Rowe pleaded guilty in January 2019 and was sentenced to life without parole.
Two different Parabon techniques touched this case, over a year apart. The 2017 composite face generated nothing. The 2018 ancestry search, run on the same DNA sample, is what led law enforcement to Rowe.
A machine-learning model narrowed an unidentifiable DNA sample down to a predicted face and a family tree, and human investigators spent weeks confirming it before anyone got arrested.
Facial recognition and DNA matching are both pattern-matching tools. They produce a probability, not a certainty.
In Mirack's case, that probability was one lead among several, and it only became an arrest after officers went and found physical evidence to confirm it.
The bad guys are always one step ahead of everybody else. In the age of AI, that step is shrinking.
Things I think about
The surface area of the human lungs, if spread flat, would cover a tennis court.
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