Bryan Kohberger's Amazon records are 'catastrophic' for defense, 'smoking gun' for prosecutors, experts say
New court filings in the Idaho student murders case could severely handicap suspect Bryan Kohberger's defense, according to legal experts – he allegedly purchased a Ka-Bar knife on Amazon months before the murders and then shopped for a replacement days after they took place.
Bryan Kohberger, a 30-year-old former criminology Ph.D. student, is accused of using a large, bladed weapon to kill four University of Idaho undergrads – Madison Mogen, 21, Kaylee Goncalves, 21, Xana Kernodle, 20 and Ethan Chapin, 20.
According to Latah County Coroner Cathy Mabbutt, all four victims died with multiple stab wounds. At least two of them were so intoxicated at the time of the attack that they were unable to resist at all, prosecutors wrote in court filings.
Under Mogen's body, police found a Ka-Bar knife sheath, stamped with a United States Marine Corps logo and allegedly containing Kohberger's DNA on the snap.
Prosecutors revealed in court filings this week that he allegedly bought a Ka-Bar, a sheath and a sharpener on Amazon in March 2022, months before the murders. Then, in the weeks after the murders, his Amazon app "click activity" allegedly shows he was browsing for a replacement.
Experts say the shopping list will be difficult for the defense to explain away, especially based on the timing and the specific details about what Kohberger was allegedly looking at.
"There's always kind of this lore around that using a knife in a murder is particularly personal," said Edwina Elcox, a Boise defense attorney who has been following the case. "And then the time frame of the search that links him, if this is correct, to this murder weapon shows a significant level, or at least I'm sure the prosecution would argue, shows a significant level of premeditation."
She said that the slate of newly revealed evidence against Kohberger indicates prosecutors may have a stronger case than previously known.
Read the filing:
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Kohberger's defense team has asked the court to keep his Amazon records out of the trial.
"The information that is publicly available is that …the murder weapon, other than the sheath, has never been recovered," Elcox told Fox News Digital. "And then he is searching for this very, very specific item. This is beyond a catastrophic fact to the defense…I do not know how you explain that away."
For Joseph Giacalone, a retired NYPD sergeant and cold case investigator, the Amazon business records are yet another tool in the digital era that he believes will increasingly help law enforcement solve crimes going forward.
"Electronic evidence is gonna bring this case to a head for sure – it's amazing," he told Fox News Digital. "I said cellphone records, internet records and video surveillance are things that are gonna solve most cases going forward, but having this type of information is extremely damaging."
Prosecutors made the revelation in response to Kohberger's defense team trying to have evidence of his Amazon activity kept out of the trial, arguing in part that the retail giant's algorithm "shapes user behavior" by serving up items it predicts shoppers want.
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"Applying the test for relevancy, first, Kohberger’s click activity which shows a purchase of a Ka-Bar knife and sheath before the homicides, makes it more probable (than it would be without the evidence) that the Ka-Bar sheath found at the crime scene was Bryan Kohberger’s," Latah County Deputy Prosecutor Ashley Jennings wrote in a court filing made public Wednesday evening.
"Second, Kohberger’s click activity after the homicides makes it more probable (than it would be without the evidence) that Kohberger had a reason to search for a Ka-Bar knife and sheath after the homicides."
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Judge Steven Hippler this week denied Kohberger's request to have an expert testify about the Amazon data at a hearing next month. He has not yet ruled on the motion to exclude the evidence.
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"This is the smoking gun evidence in the case," said Neama Rahmani, a former federal prosecutor in Los Angeles who has been following the case.
WATCH: Former prosecutor breaks down Bryan Kohberger’s Amazon history
The DNA connects Kohberger to the crime scene, and his Amazon history undermines a defense theory that it could have been planted, he said.
"This was a big mistake by Kohberger, who was otherwise very careful about covering his tracks," he added.
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Kohberger was pursuing a Ph.D. in criminology at Washington State University, just 10 miles down the road from the University of Idaho crime scene.
"I think he fancies himself…as remarkably intelligent, but as somebody who has studied this field, you know that law enforcement and their searches cast a wide, wide net," Elcox told Fox News Digital. "Having this in a searchable history format is…OK, you just have to wonder, I don't think you're maybe as smart as you thought you were."
Prosecutors have also alleged they traced his car, a white Hyundai Elantra, to and from the crime scene, that an eyewitness saw a masked man inside the home just after the murders, and that phone records also corroborate their alleged timeline of events. But Kohberger was not identified as a suspect until more than a month after the slaying with the help of investigative genetic genealogy.
While legal experts say the Amazon history is damming evidence, it also raises new questions for people who study the criminal mind, a topic Kohberger himself had studied at the graduate level. Was a suspect looking to replace a missing sheath, after leaving one behind at the crime scene, or a budding serial killer taking steps toward another kill?
"I don’t think this killing was a one off – I think…whoever did this, they were likely to kill again," Dr. Kris Mohandie, a criminal psychologist, told Fox News Digital. "If it was him, why would he kill like that unless he enjoyed it? Further, he was interested in serial killers."
And although whoever committed the crime is believed to have taken steps to conceal their tracks, he added killers always make a mistake that catches up to them.
"I’ll guarantee you that scene didn’t have one fingerprint of his on it, nor did it have anyone else’s," said John Kelly, a criminal profiler who has been following the case. "Because whoever did it wiped it down so well."
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While search warrants show police recovered knives after Kohberger's arrest, none have been publicly identified as a potential murder weapon.
Kohberger's trial is scheduled to begin Aug. 11 in Boise.
He could face the death penalty if convicted. A judge entered not-guilty pleas on his behalf at his arraignment in May 2023.