DNA links Bryan Kohberger to Idaho murders: prosecutors

DNA from a cheek swab has directly tied University of Idaho murder suspect Bryan Kohberger to the knife sheath left at the scene of the quadruple slayings, according to a new court filing.

The Idaho State Police Lab “located DNA on the Ka-Bar knife sheath” that was found on a “bed next to the bodies” of 21-year-old friends Madison Mogen and Kaylee Goncalves, Latah County prosecutors said.

“The sheath was face down and partially under both Madison’s body and the comforter on the bed,” the latest filing noted of the Nov. 13 crime scene.

Initial attempts to match the DNA using genetic ancestry data “pointed law enforcement toward” Kohberger — but “did not provide law enforcement with substantive evidence of guilt,” the filing noted.

Investigators then collected trash from Kohberger’s parents’ house in Pennsylvania, where he was staying when he was eventually arrested Dec. 30.

“That comparison indicated the DNA found on the trash belonged to the biological father of the individual who left the DNA on the Ka-Bar knife sheath,” the filing stated.

“Law enforcement then collected DNA from Defendant via buccal swab,” the filing said, with that cheek sample used for a more traditional direct DNA comparison.

“The comparison showed [a] statistical match — specifically, the [DNA] profile is at least 5.37 octillion times more likely to be seen if Defendant is the source than if an unrelated individual randomly selected from the general population is the source,” the filing said.

An octillion is a number followed by 27 zeros.

Prosecutors said in their motion that they do “not intend to enter” the less specific genetic ancestry data into evidence at trial.

“Instead, the State has relied on and will continue to rely on the [DNA] analysis comparing Defendant’s DNA to the DNA on the Ka-Bar knife sheath to establish Defendant’s guilt,” prosecutors said.

Kohberger, 28, has been indicted on four counts of first-degree murder in the stabbing deaths of Mogen and Goncalves as well as roomate Xana Kernodle, 20, and her boyfriend Ethan Chapin, 20. 

He also faces four charges of felony burglary over the shocking break-in at the students’ off-campus digs in Moscow, Idaho.

His lawyer has entered a not guilty plea on his behalf. His trial is scheduled for Oct. 2.