BOISE, Idaho — For the first time, prosecutors in the University of Idaho student homicides case have acknowledged that investigators employed an advanced DNA technique more commonly used in cold cases to land on Bryan Kohberger as the suspected killer.
The FBI submitted DNA found at the Moscow crime scene to one or more public genealogy databases to establish familial ties to the alleged perpetrator, according to newly released court records. The since-deleted DNA profile that federal agents created, on online services like Ancestry.com or 23andMe, “resulted in the lead that pointed law enforcement to” Kohberger, Latah County Prosecutor Bill Thompson wrote.
The process, known as investigative genetic genealogy (IGG), was previously reported by several news outlets, including Slate and The New York Times, but never before confirmed by officials involved in the case. The probable cause affidavit filed to justify Kohberger’s December arrest, for example, contains no reference to use of the method during the seven-week investigation following the Nov. 13 slayings.
Kohberger, 28, a former Washington State University graduate student of criminology, is charged with four counts of first-degree murder and one count of felony burglary. His trial is scheduled to begin Oct. 2, and he could face the death penalty if prosecutors choose to pursue it.
The four victims were U of I seniors Madison Mogen and Kaylee Goncalves, 21, junior Xana Kernodle, 20, and freshman Ethan Chapin, 20. All four students were stabbed to death at an off-campus home on King Road where the three women lived, while two other housemates went unharmed. Chapin was Kernodle’s boyfriend and stayed over for the night.
In recent years, law enforcement has used the genealogical technique to solve high-profile cold cases across the U.S. Most notably, IGG was applied to identify and prosecute California serial murderer Joseph James DeAngelo, otherwise known as the Golden State Killer, in 2018.
And increasingly, law enforcement is turning to IGG in active investigations.
FBI sent tip to local detectives
Moscow police found a tan leather sheath for a combat-style knife next to Mogen’s body in her bed and later located a single source of male DNA on its button snap. The Ka-Bar brand sheath, which included a U.S. Marine Corps insignia, was left face down, partially under Mogen’s body and the comforter, the new court filing detailed.
Based on the genealogical evidence that identified Kohberger, the FBI sent a tip to local law enforcement to investigate him, Thompson wrote. But other more traditional investigative and DNA methods were used to identify and charge Kohberger, he said.
“In this case, investigators used lGG to begin the process of developing a lead to the individual who left DNA on the Ka-Bar knife sheath,” Thompson wrote. “The IGG process pointed law enforcement toward (Kohberger), but it did not provide law enforcement with substantive evidence of guilt.”
In late December, investigators acquired trash left at the home of Kohberger’s parents in eastern Pennsylvania, where he was staying at the time of his arrest. The Idaho State Police Lab in Meridian tested that evidence to confirm the DNA left behind in the trash to be the biological father of the person whose DNA was on the knife sheath, police previously disclosed in the affidavit.
A swab from inside of Kohberger’s cheek was later compared to the DNA found on the knife sheath and “showed a statistical match,” Thompson wrote in the new court filing.
After Kohberger was in custody, the FBI deleted the genealogy profile on the public website, per U.S. Department of Justice policy, Thompson wrote.
No investigative timeline is included in the new court filing. Investigators possessed Kohberger’s name by Dec. 19, The New York Times reported. Investigators filed for their first search warrant specifically related to Kohberger — for his cellphone location data — on Dec. 23, the Idaho Statesman previously reported.
Through the discovery process, Kohberger’s defense has for nearly two months sought from the prosecution all investigative records related to the genetic or DNA techniques that law enforcement used in the case against its client.
Citing Idaho law, the prosecution continues to resist releasing the documents, arguing it is immaterial to the case and should be restricted. Prosecutors for now don’t plan to introduce IGG evidence during trial, Thompson wrote, and either haven’t seen some of the FBI records or don’t possess them.
Judge John Judge of Idaho’s 2nd Judicial District Court, who is overseeing the case, scheduled a hearing for June 27 in Latah County to address the defense’s motion to compel discovery. Judge also will consider the defense’s request for a pause in court proceedings while it continues to wait on delayed grand jury indictment records from the prosecution.
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