A prosecution filing in an Idaho court last week offers the first confirmation that detectives found “a statistical match” between the DNA of University of Idaho murders suspect Bryan Kohberger and DNA found on a knife sheath left by one of the victim’s bodies.
Kohberger is charged with killing Madison Mogen, Xana Kernodle, Ethan Chapin, and Kaylee Goncalves early in the morning on November 13, 2022. An extensive investigation led to his arrest at his parents’ Pennsylvania home on December 30, and a key piece of evidence found during that investigation was the knife sheath.
The motion from Prosecuting Attorney Bill Thompson and Special Assistant Attorney General Jeff Nye — obtained by NewsNation’s Brian Entin — is part of a series of back-and-forth filings between prosecutors and Kohberger’s defense as they wrangle over what materials can be handed over to the defense from the grand jury that indicted Kohberger last month.
Defense Attorney Anne Taylor has asked for all materials from the grand jury, without which, she says, Kohberger and his attorneys cannot determine whether to contest the indictment itself. But Thompson has argued that the defense is only allowed transcripts, audio recordings, and jurors notes, and his motion for a protective order, filed on Friday, seeks to preserve some of the investigative genetic genealogy work done by the FBI prior to Kohberger’s arrest.
That work, based on DNA from the knife sheath, contains names of “hundreds of innocent relatives of the family tree” investigators created as they tried to track down a suspect and should be protected from release.
061623 States Motion for Protective Order.pdf.(Null) by kc wildmoon on Scribd
But the prosecutors explain the difference between that work and DNA work done by the Idaho State Police first on the DNA found on the sheath and then DNA taken directly from the suspect, as CrimeOnline previously reported.
State police had previously worked up a short tandem repeat (STR) analysis from the DNA found on the sheath, the motion explains. They found no match in criminal databases from that, which led to the FBI’s single nucleotide polymorphism (SNP) profile, which is used in genetic DNA databases such as Ancestry and 23andme. That led to a family tree pointing to Kohberger — DNA found in the trash at the Kohbergers’ Pennsylvania home was from the suspect’s “biological father” — but no “substantive evidence of guilt.”
“The FBI did not, for example, conduct a direct comparison between the SNP profile from the Ka-Bar knife sheath and Defendant’s SNP profile,” the motion reads. “That type of direct comparison required the more traditional STR DNA analysis, which was conducted by the Idaho State Police, not theFBI.”
Once investigators obtained Kohberger’s DNA through a search warrant, they handed those samples over to state police to compare with the DNA found on the sheath.
“The comparison showed a statistical match — specifically, the STR 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 motion says.
All of that information was provided to show the court that the FBI’s investigative genetic genealogy work up, while helpful in the preliminaries, ultimately was not used to establish probable cause for Kohberger’s arrest, was not presented to the grand jury, won’t be presented as evidence at trial, and therefore shouldn’t be part of discovery.
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[Featured image: This image provided by the Latah County Jail shows Bryan Kohberger. The man accused in the November slayings of four University of Idaho students is back in Idaho, where he’s charged with four counts of first-degree murder. Authorities are expected to move quickly on a first court appearance, possibly as early as Thursday, Jan. 5, 2023. (Latah County Jail via AP)]
