3-person mixture of unknown DNA found under fingernails of Idaho murders victim, filing shows

BOISE, Idaho -- A three-person mixture of unknown DNA was found under a 21-year-old University of Idaho student's fingernails after she and three other students were killed at an off-campus home in November 2022, a new filing reveals.

The new evidence from victim Madison Mogen came more than two years after she and Kaylee Goncalves, 21, Xana Kernodle, 20, and Ethan Chapin, 20, were fatally stabbed in Moscow, Idaho. Bryan Kohberger, a Washington State University graduate student in criminology, faces four counts of first-degree murder.

In a motion filed last Monday, the defense asked that the DNA evidence be kept from the jury in Kohberger's upcoming death penalty trial because jurors could believe the DNA is Kohberger's, and according to the defense, it is not.

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"Allowing such testimony would violate Mr. Kohberger's Federal and State Constitutional rights to due process, a fair trial, effective assistance of counsel, and confrontation of witnesses," argues Bicka Barlow, an attorney specializing in forensic DNA evidence who was added to the defense's legal team recently.

A not guilty plea has been entered on Kohberger's behalf, and his trial is set to begin in August. He faces the death penalty if convicted.

In grand jury testimony, forensic scientist Jade Miller discussed the test results on a swab of fingernail clippings from Mogen's left hand, according to the motion. The defense argued that the testimony would confuse and mislead the jury, adding that the evidence is overly prejudicial.

The document shows there was preliminary testing done on the fingernail clippings and a "likelihood ratio" was calculated that according to the defense, proved to be inconclusive. The motion states testing did provide a "likelihood ratio for Mr. Kohberger" from the analysis but any conclusion is redacted in the filing.

It would prejudice Kohberger in that it might allow the jury to infer that the inconclusive data would mean that his DNA might be present in the sample, the defense argued.

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According to the defense motion, the testing involved a comparison of hypotheses, "not a statement of identity or probability of identity."

Two hypotheses were looked at: One is that the DNA belongs to Madison Mogen, her best friend Goncalves and one unknown unrelated person. The other is that the DNA belongs to Mogen and two unrelated individuals.

Mogen, a senior marketing major from Coeur d'Alene, and Goncalves were found dead on the same bed at the Kings Road home on November 13, 2022.

The revelation likely means that the defense has more in their arsenal with additional DNA finds, said Misty Marris, an attorney who has closely followed the Kohberger case. The fingernail DNA may not actually be related to the crime, she said.

"When you see it under the fingernails, the argument is going to be...that there's a scratch that somebody fought back," Marris explained. "From the prosecution perspective, the argument is, well, it's not necessarily, because there's lots of different ways DNA can end up somewhere."

Kohberger excluded from DNA mixture, defense argues

The defense states they did independent lab testing that excluded Kohberger from the DNA mixture, according to the filing.

However, the defense admits this evidence was presented to a grand jury by prosecutors as they were seeking an indictment in early 2023. They also write, "the state argued that the testimony was presented to the grand jury as exculpatory, and an effort to elicit favorable evidence for Mr. Kohberger."

At this point, the court has not posted a response from prosecutors.

The prosecution has an ethical obligation and duty to turn over everything that can be exculpatory, Marris said.

The defense will likely argue that there's reasonable doubt that Kohberger committed the murders, she said.

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"Their argument is going to be that once that investigative genetic genealogy match was made and Kohberger was identified, that law enforcement essentially put on blinders," Marris said. "They didn't care about anything else, so much so that they didn't even care that there is additional DNA evidence, both at the property and now on the person of one of the students."

To prove reasonable doubt, the defense will likely argue that there was a significant failure in the investigation to pursue any and all possible paths to find the culprit of the heinous crime, Marris said. "You have this entirely other set of potential DNA that could have led investigators had they pursued it to somebody else, and that's going to be a huge component of the argument," she said.

The revelation comes as several pieces of DNA evidence have been challenged by the defense.

The prosecution's most important piece of evidence is a DNA sample taken from a knife sheath left at the crime scene. Investigators then used investigative genetic genealogy, a forensic field combining DNA analysis with genealogical research, to connect that sample to Kohberger's family, according to prosecutors. Subsequent DNA testing found Kohberger was a "statistical match" to the sample, leading to his arrest, according to prosecutors.

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To combat that evidence, his defense team has repeatedly questioned the use, legality and accuracy of the DNA testing done in each step of the process. In a closed hearing last month, testimony from several witnesses raised questions about how investigators had used the DNA sample from the knife sheath to identify Kohberger as a suspect. Further, the defense's addition of Barlow to its legal team bolsters their expertise on the topic.

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