How DNA Dispute Could Impact Bryan Kohberger Case

An attorney has explained why Bryan Kohberger's defence team is attempting to cast doubt on the DNA evidence the prosecution is relying on in the University of Idaho Murder case.

On August 9, Dr. Leah Larkin, a genealogist expert working with Kohberger's, defense team, filed an affidavit calling into question the reliability of the use of genetic genealogy, which investigators used prior to arresting him.

Criminal Defense attorney Rachel Fiset, managing partner of Los Angeles-based Zweiback, Fiset & Zalduendo, spoke to Newsweek and said the defense hopes to "confuses the jury regarding the issue of DNA science" and its reliability in this case.

Newsweek also spoke to Biology Professor Greg Hampikian of the University of Idaho and co-director of the Idaho Innocence Project about how the points raised by Larkin are valid and the potential issues that can arise with authorities' use of genetic genealogy in criminal investigations.

Detectives were able to arrest Bryan Kohberger after a knife sheath, found at the home where the victims Kaylee Goncalves, 21, Madison Mogen, 21, Xana Kernodle, 20, and Ethan Chapin, 20, were found stabbed to death, was eventually traced back to him.

Kohberger, 28, is the sole suspect in the quadruple killing and the prosecution has said that the suspect broke into the students' home in the early morning hours of November 13, 2022, and fatally stabbed each of the victims.

His defense lawyers entered a not-guilty plea on his behalf back in May to the four counts of murder and one count of burglary connected to the investigation. Kohberger was a Ph.D. criminology student and teaching assistant at Washington State University's campus at the time of the killings. Newsweek has contacted the Kootenai County Public Defender office via email for comment.

"The defense is doing what they can to discredit the DNA evidence that puts Kohberger at the scene of the crime," Fiset said.

"Casting doubt on the methodology used to collect the DNA, as well as the reliability of the DNA evidence, is the best manner they have to do this.

"The defense expert will likely testify to the jury regarding the potential of less reliable results when tracing genealogy through DNA as opposed to direct DNA sampling. The prosecution, however, will obtain a competing expert to debunk the defense expert's opinion.

"The best-case scenario for the defense is that the expert testimony on each side confuses the jury regarding the issue of DNA science such that the confusion raises some doubt regarding the damning DNA evidence against Kohberger."

Before detectives were able to arrest Kohberger, they first used genetic genealogy to determine he was a suspect and the affidavit by Larkin scrutinizes this process.

What is Genetic Genealogy?

Genetic genealogy is a field of genealogy and family history research that combines genealogical DNA tests and traditional genealogy methods to discover how individuals are related, according to Sequencing.com, a company that provides DNA tests and stores DNA data.

Through this method, the FBI was able to track down Kohberger by tracing distant relatives through genetic genealogy databases. They then collected a sample of his father's DNA to confirm Kohberger's identity.

In the affidavit, Larkin stated that genealogy tests have become more available in recent years thanks to companies like AncestryDNA, 23ndme and other smaller companies, but they are not the same as or as reliable as the STR (short tandem repeat) standard forensic tests done in laboratories.

"Unlike standard forensic STR tests which are used to identify individuals, genetic genealogy testing identifies possible relatives," she said in the document.

Detectives still have to do traditional police work following this and ensure a suspect is in the area, has a motive and opportunity to commit a crime, which authorities have said they have done in Kohberger's case.

Genealogy & Criminal Cases

Larkin also concluded her affidavit by raising the point the use of genetic genealogy in criminal cases, after individuals may have knowingly or unknowingly supplied their genetic information, has privacy implications that may apply to the Kohberger case.

Professor Hampikian emphasized to Newsweek the importance of scrutinizing the use of genetic genealogy in criminal cases.

"It is possible a person could send their DNA to one of these companies, the police will use it against that person and they never signed up to allow the police to do it," he said.

"Is that okay? I think it is okay if you are solving a mass murderer, I think the general public would [agree].

"What if the police are wrong in the genealogy and we have a wrongful conviction that was based on somebody's DNA that was sent to one of the companies, there was some sort of mix up along the way.

"Then it will become an issue, but until then the FBI and others think it is safe."

Hampikian also noted that the public has not been made aware who sent the DNA in for one of the genealogy tests that was later connected to Kohberger's family. He added that it was even possible the suspect has previously used one of the ancestry services.

He added that police have said they got a sample from Kohberger and processed it through the non-genealogy ways in the lab and made a traditional match with the DNA found on the knife-sheath. He noted some defenses in cases do not even raise the point of genetic genealogy being used as they "do not see it as important to their case."