How a DNA technique to pin Bryan Kohberger as Idaho murder suspect could shape case law

What if Bryan Kohberger, the man charged with the University of Idaho student stabbings, helped lead police right to him?

His own attorneys may raise the question — including at trial — in their efforts to defend him. Kohberger is accused of killing four U of I students in November 2022 in a case that continues to collect national intrigue.

By the end, it could create new case law for criminal investigations across the U.S., legal scholars told the Idaho Statesman.

Anne Taylor, Kohberger’s lead public defender, said she has repeatedly pored over law enforcement’s evidence summary to justify his arrest and still wants to know what led police to her client as the suspect.

“The clear picture that I’m concerned about is the state’s pathway of how Bryan Kohberger comes to their attention and is identified,” Taylor told the court at a hearing last month. “Over a year into this case and … we’re not sure. I know different pieces, but I don’t know where they fit together.”

Depending on the circumstances that come to light, it could be grounds for a constitutional rights challenge over the methods police used to find and charge Kohberger, his defense attorneys have said.

Anne Taylor, lead public defender for Bryan Kohberger, who is accused of killing four University of Idaho students in November 2022, said she’s still unclear on what led police to her client.
Anne Taylor, lead public defender for Bryan Kohberger, who is accused of killing four University of Idaho students in November 2022, said she’s still unclear on what led police to her client.

In a probable cause affidavit, police described using traditional investigative techniques to arrive at Kohberger as the suspected killer and close an almost seven-week manhunt that confoundingly ended on the other side of the country in eastern Pennsylvania. DNA evidence also factored for police to allege they had their suspect, but only after the other elements established through surveillance footage of the suspect’s car and Kohberger’s cellphone location data fell into place, according to the affidavit.

But six months after Kohberger’s December 2022 arrest, state prosecutors acknowledged for the first time that an advanced DNA technique known as investigative genetic genealogy, or IGG, initially led investigators to Kohberger. The process involves submitting DNA located at a crime scene to public genealogy websites to build a family tree related to possible suspects and narrow an investigation. Police made no mention of the FBI’s use of IGG in the affidavit.

A single source of male DNA was pulled and processed from a leather sheath for a Ka-Bar combat-style knife discovered under one of the four stabbing victims at the off-campus Moscow home. The four U of I students were seniors Madison Mogen and Kaylee Goncalves, both 21, junior Xana Kernodle and freshman Ethan Chapin, both 20.

At the time, Kohberger, 29, was a graduate student of criminal justice and criminology at Washington State University in Pullman, about 9 miles west of Moscow. Kohberger’s attorneys have said there were no connections between him and the victims.

In the court filing that revealed the FBI’s use of IGG, Latah County Prosecutor Bill Thompson argued that the state was not required to disclose the DNA technique. Prosecutors did not intend to introduce it at trial, he said, and it was irrelevant to Kohberger’s defense. Instead, they planned to present a comparison of DNA evidence police obtained from a swab of Kohberger’s cheek during his arrest against the knife sheath DNA, which showed a “statistical match,” Thompson said.

“The IGG process pointed law enforcement toward (Kohberger), but it did not provide law enforcement with substantive evidence of guilt,” Thompson wrote in the court filing. “The IGG information is not material to the preparation of the defense.”

For eight months, the two sides fought over the release of the IGG records to the defense through the legal process known as discovery. Judge John Judge of the 2nd Judicial District in Latah County, who is overseeing the Kohberger case, last month granted the defense at least some of the FBI’s records from the IGG process. What was turned over, and what may have been withheld, is unclear to the public because the documents were sealed.

Tiffany Roy, a longtime forensic DNA expert, said Kohberger’s defense team is perhaps working toward leveraging its recent access to the FBI records to make a constitutional rights claim against illegal searches and seizures under the Fourth Amendment. Prosecutors’ attempts to conceal information about use of IGG to identify a suspect alone should give the public pause, Roy, who also holds a law degree, said in a phone interview with the Statesman.

“I don’t understand the government’s argument here,” Roy said. “You have an obligation to expose every part of your investigation, and then we decide what is important. If the FBI were doing the right thing, they wouldn’t have to make these arguments. Put it all out on the table.”

Prosecutors won’t say which websites FBI used for IGG

Already, the Kohberger case has broken new ground, according to David Gurney, director of the IGG Center and professor of law and society at Ramapo College of New Jersey. Never before in a case has the defense team received access to this level of IGG records in discovery, he said.

The next battle between the attorneys on each side of the Kohberger case could be over whether the defense will be allowed to present IGG evidence to the jury at trial, Gurney told the Statesman by phone. IGG records have been introduced at trial a couple of times before, he said, but only when prosecutors chose to do so when they felt it beneficial to their case.

“It’s potentially novel in that way,” Gurney said, explaining the defense’s potential strategy if it comes to fruition. “I would try to get all of this information in front of the jury. … I would try to just muddy the waters by showing, ‘Oh, the state did all these bad things, so therefore you should just not trust them at all.’ ”

For instance, prosecutors have not publicly disclosed which genealogy websites police used to land on Kohberger — only that the FBI submitted the crime scene DNA to “one or more” of the publicly available services. Law enforcement primarily works with two lesser-known websites called GEDMatch and FamilyTreeDNA, but has at least in some past instances found ways to access DNA profiles on a more widely used platform with more users, Gurney and Roy said, and other IGG experts testified at an August hearing for Kohberger’s defense.

“They have access to GEDMatch and FamilyTreeDNA and that’s it,” Roy said. “So if they didn’t get what they wanted from those databases and need to fish around in other databases, I would be really uncomfortable with that.” and 23andMe are much more popular competitors in the genealogy industry, but neither of the direct-to-consumer services cooperates with law enforcement, according to their websites. Instead, investigators have in other cases previously reviewed DNA profiles on MyHeritage, yet another of the genealogy platforms available online, Gurney and Roy said.

“The reason that they would have done it, if they did, is it gives you access to a much larger number of people, a much larger number of matches, and, in theory, that will make your job easier,” Gurney said.

If the IGG records now in the defense’s possession divulge that FBI investigators conducted themselves in an improper way or violated expectations of privacy to get to Kohberger, it may help create legal openings for creating doubt about the evidence, they added.

The FBI used an advanced DNA technique called investigative genetic genealogy to initially arrive at Bryan Kohberger as the suspect in the University of Idaho student murders in November 2022.
The FBI used an advanced DNA technique called investigative genetic genealogy to initially arrive at Bryan Kohberger as the suspect in the University of Idaho student murders in November 2022.

“It’s a good tool, but the question is, does it violate civil rights?” said Greg Hampikian, a biology professor at Boise State University who heads the Idaho Innocence Project. “Some say that it’s just another technique, but this technique involves something more intimate than a body cavity search. It’s an every single cell in your body search.”

Faced with the task of defending Kohberger, Los Angeles-based criminal defense attorney Joshua Ritter said he would pursue the same approach and try to create questions in the minds of jurors about the DNA evidence. The host of True Crime Daily’s “The Sidebar” podcast said the whole case hinges on this issue, based on what prosecutors have disclosed to date.

The probable cause affidavit was well done and showed high-level police work, but the remaining evidence against Kohberger becomes “very tenuous” and “circumstantial” if the DNA is removed from the equation, Ritter told the Statesman by phone. That the defendant lived in the area, had suspicious driving habits and possibly turned off his cellphone at the time of the homicides makes for a much harder case for prosecutors to prove beyond a reasonable doubt, he said.

“I think everybody agrees this case rises and falls on that DNA,” Ritter said. “Their ability to match Kohberger to the knife sheath at the crime scene is the seminal, cornerstone piece of evidence.”

Police also said they linked the crime scene DNA to other DNA acquired from the trash they took from Kohberger’s family home in Pennsylvania. The comparison showed that the DNA from the trash was the male suspect’s biological father with nearly 100% certainty, according to the affidavit.

The critical role the case’s DNA evidence is likely to play is precisely why Kohberger’s attorneys have made it a focal point of their pretrial efforts, several attorneys and DNA experts told the Statesman. Successfully securing the IGG records was the first step.

At the August hearing, Kohberger’s defense attorneys told Judge that without the requested information, they couldn’t effectively defend their client in his capital murder case. For example, the defense shouldn’t have to take the state’s word that Kohberger’s DNA was found on the knife sheath.

The use of IGG and order of events in the Moscow homicide investigation leading up to Kohberger’s arrest are crucial to providing a sound defense, they told the court.

“We can’t articulate to you, because of the lack of the data, the sequence of exactly how they got to our client, and what happened when and in what order,” said Elisa Massoth, another of Kohberger’s defense attorneys. And, if it’s shown that law enforcement brushed up against privacy rules in their pursuit of a suspect through IGG, she said, the defense is eyeing a constitutional challenge.

Elisa Massoth, left, a member of Bryan Kohberger’s defense team, talks with lead public defender Anne Taylor during a pretrial hearing Aug. 18 at the Latah County Courthouse in Moscow.
Elisa Massoth, left, a member of Bryan Kohberger’s defense team, talks with lead public defender Anne Taylor during a pretrial hearing Aug. 18 at the Latah County Courthouse in Moscow.

‘I’m not sure if it raises constitutional questions’

Based on legal precedent, criminal defendants do not have privacy rights under the Fourth Amendment to evidence they allegedly left behind at a crime scene. Police also do not need a warrant to acquire potential evidence from discarded garbage taken to the curb.

In addition, swabs of a suspect’s cheek for DNA are legal with a search warrant. A criminal defendant who was discovered through investigative techniques, such as IGG, cannot vicariously assert the Fourth Amendment rights of others whose privacy may have been violated from a lack of consent, the group of legal experts told the Statesman.

Thompson, however, tried to get ahead of a possible Fourth Amendment claim in the Kohberger case in his arguments against Judge giving the defense the IGG records used to find him. The defense would first have to establish that the defendant had a “reasonable expectation of privacy” to allege that law enforcement committed such a violation, he wrote.

“The Ka-Bar knife sheath was abandoned at the (crime) scene, as was the DNA inside it,” Thompson wrote. “Defendant cannot show that he had a reasonable expectation of privacy in DNA left at the scene of a quadruple homicide or in the genetic information of his relatives, who voluntarily provided their own DNA to a genetic genealogy service.”

In addition, local law enforcement did not use the FBI’s IGG results in support of Kohberger’s arrest or any search warrants obtained by police, Jeff Nye, chief deputy for the Idaho attorney general’s criminal law division, said at the August hearing. The assertion would seem to target arguments that any evidence investigators produced afterward is spoiled because it was illegally obtained and therefore inadmissible at trial based on the so-called “fruit of the poisonous tree doctrine.”

Likewise, Brandon Garrett, a constitutional law professor at Duke University’s law school, is skeptical of a possible civil liberties claim over law enforcement’s use of publicly available information as part of a criminal investigation. The use of advanced genetic tools is just a few decades old, and the courts have been slow to consider granting what would essentially be a new privacy right protected under the Fourth Amendment, he said.

If a person using a genealogy website didn’t agree to allow police to include their DNA profile for IGG searches, it amounts to a possible violation of the terms of service by law enforcement, Garrett said in a phone interview with the Statesman.

“But I’m not sure if it raises constitutional questions,” he said. “It raises a larger question of, is there a constitutional right to genetic privacy? And we don’t have clear answers. … We don’t know what the courts will do with it, even if it is super interesting and an important problem.”

At the August hearing, Judge prodded the defense on the relevance of the IGG records, including in a hypothetical situation where the FBI was found to have skirted the rules to arrive at Kohberger. He questioned whose constitutional rights would have been violated in the circumstance.

Judge John Judge of Idaho’s 2nd Judicial District in Latah County oversees a pretrial hearing for Bryan Kohberger in August. He awarded at least some investigative genetic genealogy records to the defense.
Judge John Judge of Idaho’s 2nd Judicial District in Latah County oversees a pretrial hearing for Bryan Kohberger in August. He awarded at least some investigative genetic genealogy records to the defense.

“I don’t want to get into the Fourth Amendment issue there. I think that’s a gray area, for sure,” Judge said.

“What it suggests is that folks should probably be cautious about sending their spit to some corporation. But I don’t know how much that’s going to bear on what ultimately happens given the sequence of what happened with Mr. Kohberger,” he added.

After police found the knife sheath, the Idaho State Police crime lab in Meridian located the DNA on its button snap, the affidavit said. No matches were found in the national criminal offender database, so the DNA was sent to an unidentified private lab to begin the IGG process, Thompson said in the court filing.

That lab is believed to be Texas-based Othram, which Idaho State Police said has maintained a contract with the state for forensic genetic work, including IGG, since summer 2021. The defense has twice said the private lab was Othram, though prosecutors have never confirmed the name of the lab involved, and Othram has not responded to Statesman requests for comment.

Law enforcement working the Kohberger case decided the FBI would take over the IGG process and investigators began building family trees to try to get to a suspect. The FBI then sent a tip to local police to investigate, but produced limited records in the process and removed the DNA profile from the genealogy websites they used, per Department of Justice policy, Thompson wrote.

Nonetheless, Judge at least partially awarded the IGG records to Kohberger’s defense team. Ritter, the Los Angeles-based criminal defense attorney, said the decision prevented a possible constitutional challenge under the 14th Amendment over alleged due process violations from prosecutors refusing to turn over records showing how police came to suspect Kohberger.

“The state’s argument that the IGG investigation is wholly irrelevant since it was not used in obtaining any warrants and will not be used at trial is well supported,” Judge ruled in October. “Nonetheless, Kohberger is entitled to view at least some of the IGG information in preparing his defense even if it may ultimately be found to be irrelevant.”

A pretrial hearing is scheduled for Wednesday in Moscow to clarify how the defense may use the IGG records, including which experts may review them.

Kohberger submitted for DNA testing, neighbor says

Still, another scenario could exist. The FBI may have used the crime scene DNA to conduct an IGG search and instead landed directly on Kohberger’s own DNA profile on a genealogy website. Ostensibly, this would give them a direct hit for the possible suspect.

Kohberger more than a year before the U of I student homicides told a fellow WSU graduate student living in the same on-campus housing complex in Pullman that he had submitted his DNA for testing to learn about his ancestry, the neighbor told the Statesman last year. The neighbor spoke on condition of anonymity over privacy concerns.

“He talked about his ancestors,” the neighbor said in an interview from the entry of his apartment. “He had some sort of DNA test. I don’t know how he got to that point. … It was just interesting to him.”

Suddenly, the possible constitutional implications would no longer be about the DNA left at a crime scene or the rights of those genealogy website customers who didn’t agree to allow law enforcement to access their profiles for use in a criminal investigation. Under this potential scenario, Kohberger himself would not have consented for his DNA profile to be used in such a way, Gurney said.

Bryan Kohberger, 29, is charged with four counts of first-degree murder in the stabbing deaths of University of Idaho students in November 2022. He faces the death penalty if convicted.
Bryan Kohberger, 29, is charged with four counts of first-degree murder in the stabbing deaths of University of Idaho students in November 2022. He faces the death penalty if convicted.

“I think that scenario could be really interesting from a constitutional perspective,” he said. “It’s not clearly a vicarious claim, because it’s him making a claim for himself.”

The chances of that remain low, Gurney said, even if Kohberger previously submitted his DNA to a genealogy website. Most people use either or 23andMe, which law enforcement can’t access, and requires customers to use each company’s proprietary testing kits.

But other possibilities remain, he acknowledged. Kohberger could have downloaded his DNA profile from either service and then submitted it to GEDMatch or FamilyTreeDNA, but still not agreed to allow law enforcement to use it in its investigations. Thus, the potential constitutional claims for a criminal defendant.

“It’s never happened in any case that I’m aware of,” Gurney said. “We’ve had cases where there’s a sibling or parents or something. But no one that I know in this field has ever encountered a violent criminal who was so stupid as to upload their own DNA into … any of these databases.”

In yet one other scenario, Kohberger could have originally sent his DNA to MyHeritage to produce a DNA profile. FBI investigators then would have had to upload the crime scene DNA to the website while conducting an IGG review, against the terms of service but as the federal agency has previously been known to do, Gurney and Roy said, and landed on the exact match for the suspect.

“I think it would be unethical,” Gurney said. “It would be something that I would strongly urge them not to do, but it’s not illegal for them to access the MyHeritage database, if that’s indeed what happened.”

Even so, Ritter saw the possible constitutional implications if the FBI did violate MyHeritage’s terms of service, which in turn could be argued also violated Kohberger’s Fourth Amendment rights. Defense attorneys, he said, might be able to argue that it wasn’t only the use of his own DNA profile that infringed on his expectation of privacy but also the use of his DNA’s connections to relatives, which also would identify him, based on the agreement he struck with the genealogy company when he paid for the service.

“It might be a devil’s in the details situation,” he said. “It raises the question, ‘Is the FBI operating in that gray area and using this website that people believe has their information and is being protected from law enforcement when really it’s not?’ … He does have a direct expectation of privacy, and what is that expectation and is that outlined on that website clearly enough that he had an expectation, not only his individual profile, but any kind of collateral revelations from that DNA?”

McClatchy Chief Washington Correspondent Michael Wilner contributed to this report.