A forensic criminologist working with Bryan Kohberger’s defense was set to present a theory that the 2022 murders of four University of Idaho students involved two perpetrators.

Dr. Brent Turvey, after examining the autopsy reports of victims Madison Mogen, Kaylee Goncalves, Xana Kernodle, and Ethan Chapin, put forward this theory. This information surfaced in recently unsealed court documents, as reported by People.

Turvey argued in the court filings that “at least two suspects were involved in this attack,” referencing findings from the victims’ autopsies.

The four students tragically lost their lives to fatal stab wounds in an off-campus residence in Moscow during the early hours of November 13, 2022.

At the time, Kohberger, who was pursuing a doctorate in criminology at Washington State University, was expected to face trial for the murders in the summer of 2025. However, he opted for a guilty plea to avoid a possible death sentence, just weeks before the trial’s commencement.

Bryan Kohberger Defense Expert Believed There Could Have Been Two Killers

Had the trial proceeded, Turvey was ready to testify for the defense, indicating that the autopsy results pointed to the involvement of two killers in the gruesome incident.

Key autopsy findings, released in a newly unsealed supplemental filing from prosecutors obtained by People, concluded the four victims had been stabbed at least 150 times. Goncalves and Mogen—who were found together in a bed on the third floor—were stabbed 38 times and 28 times, respectively, with multiple wounds to their head, face, neck and chest. 

Kernodle—who investigators told ABC News may have interrupted the killer—received the brunt of the violence, suffering 67 stab wounds, while Chapin was stabbed 17 times as he lay in bed in a second-floor bedroom.

Turvey argued in his findings that it was “not reasonable” to conclude that Chapin remained in bed without waking up as Kernodle, his girlfriend, was getting attacked. 

He concluded in the report, “This evidence and context begin to suggest the existence of a second attacker.” 

He added that it appeared that Chapin and Kernodle had been attacked at the same time, making it “inconsistent with the State’s theory that these crimes were committed solely by one individual.” 

Yet, prosecutors argued in their own response, included in the unsealed filing, that “One assailant could contain two people in close proximity to each other, especially if the assailant is armed.” 

To support his theory, Turvey also wrote that the autopsy reports suggested that Goncalves’ injuries were caused by “multiple types of lethal force.” 

In their rebuttal, however, prosecutors argued that its possible for one perpetrator “to use multiple types of lethal force,” according to the court records.

Dr. Brent Turvey Points Out Evidence of Crime Scene Clean Up in Idaho Murders

Turvey’s argument also centered on evidence which he said suggested someone had tried to clean up elements of the crime scene, pointing to evidence that found blood on the walls was diluted with an unknown substance and the “absence of bloody” footprints at the scene, despite the brutal nature of the crimes.

He argued in the filing that, “The precautionary acts in this case include the execution of living witnesses; the clean-up of bloody hands, feet / foot-ware and clothing before leaving; and the disposal of said clothing along with the weapons used.”

It would be difficult, he contended, for one assailant to complete the tasks in the 15 minutes investigators suspected he was inside the home.

Prosecutors, however, refuted that claim, arguing in their response that the clean-up could have been quickly accomplished.

“Washing or wiping hands takes little time especially if preparations for cleaning are made beforehand,” they wrote, per People. “Removal of protective clothing and shoe coverings takes seconds.”

Kohberger Defense Expert Questions Why Blood Wasn’t Found in His Vehicle

Turvey also questioned why no blood evidence was discovered in Kohberger’s vehicle, writing that the vehicle had been taken “down to the metal” and no blood was found. 

In response, prosecutors said there could be a “myriad of reasons blood was not transferred to or detected” in the car. 

Latah County Prosecutor Bill Thompson laid out the prosecution’s theory of the case in more depth when Kohberger entered his guilty plea on July 2, 2025, according to previous reporting from Oxygen. He told the court that Kohberger snuck into the Moscow home through a sliding glass door off the kitchen, then went to the third-floor bedroom, where he stabbed Mogen and Goncalves. 

Kernodle—who had gotten a DoorDash order around the time of the murders—had likely been awake and encountered Kohberger inside the house. 

According to records released last year by Idaho State Police and obtained by Oxygen, Dylan Mortensen—a resident of the home who was not attacked in the violence—later told police she heard someone running on the stairs and saying “someone’s here” before she later heard someone she believed to be Kernodle crying.

Authorities believe that Kohberger then killed Chapin as he slept in Kernodle’s bed. 

After agreeing to the guilty plea, Kohberger is now serving out his life sentence inside the Idaho Maximum Security Institution in Kuna, Idaho.