Police Say Little On How Forensic Genealogy Helped Solve ID Killings

Around 4 a.m. on Nov. 13, a masked man broke into a house near the University of Idaho campus and killed four students. Early in the investigation, the Moscow, Id., Police Department was interested in the surveillance footage that captured a Hyundai Elantra near the house that morning. Police complied lists of white Hyundai Elantras registered in the area, and they identifed Bryan Kohberger, a 28-year-old criminology student as the car's owner. However, it would take another month before Kohberger would be charged with the murders, reports Slate. Investigators utilized a technique reliant on genealogy databases to determine who’d left DNA on a tan leather knife sheath found at the scene. Kohberger did not stick out among the other Elantra owners. The precise way that forensic genealogy helped investigators zero in on Kohberger has not been previously reported. This is one of the most high-profile cases in which this was used and will likely influence how law enforcement approaches it.

The use of forensic genealogy underlines how police identified their suspect, which some are suggesting is a model. Genetic genealogists say, the case embodies an emerging trend of not mentioning forensic genealogy in court documents and press conferences. The Idaho affidavit’s “thoughtful omission” of any reference to genealogy, as forensic DNA analyst Tiffany Roy put it, has reignited a heated debate about how wise of a strategy that is. According to court documents, a leather knife sheath stamped with a Marine Corps eagle containing "a single source of male DNA" on its button snap was found. Investigators turned to an alternate way of identifying DNA by uploading it to a genealogy database. Genealogists then look for partial matches, hoping to find relatives within the third-cousin range. They then began the process of building an enormous family tree, using a vast array of public records and more-traditional detective work to create a short list of people within that tree who could plausibly be the suspect. That Kohberger lived 10 miles from the crime scene and that he owned a white Elantra made him stand out. The final step was to match the crime scene DNA evidence with something Kohberger discarded, like trash. He was arrested on Dec. 30. Forensic genealogy leaders at the FBI have directed police departments to omit all references to the technique of forensic genealogy used in their investigations.