MOSCOW, Idaho — The man charged with stabbing and murdering four University of Idaho students last year provided a cheek swab to investigators -- that cheek swab was a statistical match to DNA found at the crime scene, Latah County prosecutors say in a recent court filing.
Bryan Kohberger, 28, faces four counts of murder and one count of felony burglary for the deaths of Xana Kernodle, Ethan Chapin, Madison Mogen and Kaylee Goncalves after they were found stabbed to death in a home in Moscow on Nov. 13, 2022. Kohberger was indicted by a grand jury and will face trial, set for Oct. 2 of this year.
Police previously said in an affidavit they arrived at the conclusion Kohberger was their possible suspect when they tracked his phone records and traced familial DNA to him found in a trash bin outside his Pennsylvania family home.
The FBI created a genealogical family tree where they found the DNA matched someone who was a male and a close a relative of Kohberger's father, new court filings said. Law enforcement also ran the DNA through a national database called CODIS, which has DNA profiles of convicted offenders and missing persons, but that yielded no results.
The DNA that forensic scientists were comparing to was found on a Ka-Bar knife sheath next to the bodies of Mogen and Goncalves -- but in the new court filing dated June 16, investigators followed up further.
The most recent filing is a motion for a protective order in the case, meaning an order to seal any evidence related to raw data involving the specific DNA profile and the laboratory documentation, and all information related to the creation of a genealogical family tree identifying any of Kohberger's relatives for privacy purposes.
According to this motion, an STR profile from the knife sheath was developed. An STR profile, according to the National Institute of Justice, stands for "short tandem repeat." An STR analysis can show a number of repeating protein "sequences" in someone's DNA that is specific to them.
"A collection of these can give nearly irrefutable evidence statistically of a person's identity because the likelihood of two unrelated people having the same number of repeated sequences in these regions becomes increasingly small as more regions are analyzed," the National Institute of Justice states.
Kohberger was given a cheek swab and it was compared to the STR profile.
Prosecutors said in the new filing, "The STR profile is at least 5.37 octillion times more likely to be seen if the defendant is the source than if an unrelated individual randomly selected from the general population is the source." Meaning, the profile scientists developed is more likely to be Kohberger than someone random.
The affidavit also said the knife sheath was found next to the bodies of Mogen and Goncavles, who were sleeping in the same bed. The filing on June 16 now specifies that the sheath was "face down and partially under Madison's body and the comforter on the bed."
Kohberger faces life in prison or the death penalty if convicted. A hearing to pause the proceedings so he can contest his grand jury indictment is set for June 27.
Watch more coverage of this story
Ongoing coverage of the University of Idaho investigation can be found in our YouTube playlist: