Male DNA left on a knife sheath was used to link a then-doctoral student in Washington state with the slayings of four University of Idaho students in November — and a surviving roommate came basically face-to-face with him the night of the killings, according to court documents unsealed Thursday.
A probable cause affidavit prepared by Moscow, Idaho, Police Officer Brett Payne lays out how investigators used video surveillance in the area to connect the quadruple homicide with a white Hyundai Elantra driven by Bryan Kohberger.
Kohberger, 28, was ordered held without bail at his first court appearance Thursday morning in Idaho following his arrest Dec. 30 at his family's home in northeastern Pennsylvania. He faces four counts of first-degree murder and burglary, accused of breaking into the students' rental house with the intent to commit a felony.
The arrest of a suspect about seven weeks after the killings of the students — Madison Mogen, 21; Kaylee Goncalves, 21; Xana Kernodle, 20; and Ethan Chapin, 20 — capped a period of fear and frustration in the largely rural college community of Moscow.
But Kohberger, who was a doctoral student in the criminal justice and criminology department at nearby Washington State University at the time of his arrest, was not immediately known to have an association with any of the victims.
The murder weapon, believed to be a large fixed-blade knife, has still not been recovered, Moscow police said.
The newly released court documents also don't suggest a motive for the attack, which Moscow police have said from the beginning appeared to be "targeted," although they didn't know if it was a particular occupant or the home itself that was the killer's focus.
Kohberger's public defender in Pennsylvania said last week that the suspect's family does not believe he was involved, and that he was "eager to be exonerated of these charges and looks forward to resolving these matters as promptly as possible."
Discovery of the knife sheath
Payne said he arrived at the off-campus apartment house on King Road at about 4 p.m. on Nov. 13 to assist an Idaho State Police forensics team in processing the crime scene.
As he and another officer moved through the three-level home, Payne said he walked toward a bedroom on the second floor and saw Kernodle's body on the ground. She was "deceased with wounds which appeared to have been caused by an edged weapon," he wrote. Another person, later identified as her boyfriend, Chapin, was also found stabbed in the room.
Payne said they went into another bedroom where they found the bodies of Goncalves and Mogen in the same bed with "visible stab wounds."
He then saw an object — a tan leather knife sheath — on the bed next to Mogen.
"The sheath was later processed and had 'Ka-Bar' 'USMC' and the United States Marine Corps eagle globe and anchor insignia stamped on the outside of it," Payne wrote. "The Idaho state lab later located a single source of male DNA (suspect Profile) left on the button snap of the knife sheath."
One of the housemates encounters suspect
As Moscow police asked for the public's help in the early stages of the investigation, they also said two other housemates had been home at the time of the killings but were unharmed, and were not believed to be involved in the crime.
The roommates — Dylan Mortensen and Bethany Funke — had come forward in early December in letters shared publicly to say they were struggling to accept why the lives of "four beautiful people" were taken so brutally.
Initial reports from investigators said the two were asleep during the stabbings, and that one of their cellphones was used to call 911 just before noon on Nov. 13.
According to the affidavit, Mortensen — who is identified as "D.M." — gave police the most detailed eyewitness account of the hours before the slayings.
She heard Goncalves playing with her dog at about 4 a.m., and then a short time later, heard her housemate saying, "There's someone here,” the court documents said.
Then, she said, she heard crying from Kernodle's room and a male voice saying "something to the effect of 'it's ok, I'm going to help you,'" according to the affidavit.
Kernodle was alive until at least 4:12 a.m. as her cellphone showed she was on her phone using TikTok, police said.
At 4:17 a.m., a nearby security camera picked up "distorted audio of what sounded like voices or a whimper followed by a loud thud," while a "dog can be heard barking numerous times," the affidavit said.
"D.M. stated she opened her door for the third time after she heard the crying and saw a figure clad in black clothing and a mask that covered the person's mouth and nose walking towards her," according to the court documents.
She "described the figure as 5'10" or taller, male, not very muscular, but athletically built with bushy eyebrows. The male walked past D.M. as she stood in a 'frozen shock phase.' The male walked towards the back sliding glass door. D.M. locked herself in her room after seeing the male."
It wasn't clear if the witness said she made eye contact with the black-clad figure.
Based on forensic evidence and interviews, investigators believe the four victims were killed sometime between 4 a.m. and 4:25 a.m. All of the home's occupants were in their bedrooms by 4 a.m. with the exception of Kernodle, who had received a DoorDash delivery at around that time, according to the affidavit.
Police identify a white car
The link to Kohberger began with investigators reviewing security video of streets around the crime scene and noticing a white Hyundai Elantra driving multiple times past the house just before the killings, then speeding from the area soon after in the direction of Pullman, Washington, home of Washington State University.
Investigators reviewed security video footage on the college's campus and noticed the same car leaving the campus before the attack and returning after it, according to the affidavit.
On Nov. 25, Moscow police alerted law enforcement agencies in the area to be on the lookout for white Hyundai Elantras. Four days later, campus officers at WSU noticed an Elantra registered to Kohberger. Armed with a name, investigators pulled Kohberger's driving record and found that he'd been stopped in Moscow in August. During that stop for a traffic infraction, Kohberger provided his cellphone number.
That number allowed investigators to examine where his cellphone had been around the time of the slayings.
In addition, "the photograph of Kohberger shows that he has bushy eyebrows. Kohberger's physical description is consistent with the description of the male D.M. saw inside the King Road Residence on November 13th," according to the affidavit.
Suspect's cellphone use investigated
Authorities had obtained a search warrant for cellphones used near the crime scene around the time of the killings, according to the affidavit.
But Kohberger's phone did not come up in that search. Investigators suspected that he had turned his phone off before the killings.
Another search warrant, granted Dec. 23, gave investigators Kohberger's cellphone location during the 24 hours before the killings and the 24 hours afterward. That information showed Kohberger left his home in Pullman a couple of hours before the victims were killed before disabling or turning off his phone, according to the affidavit. The phone did not go back online until after their deaths when it traveled from Idaho and to Pullman.
A few hours later, after 9 a.m. on Nov. 13, Kohberger traveled from Pullman to an area close to the crime scene and quickly returned home.
Investigators got another search warrant, this time to track Kohberger's phone further back in time, to see if he had stalked any of the victims, contacted them or staked out the King Road home. Those records revealed that Kohberger had been near the King Road home at least 12 times between June and the day of the slayings, according to the affidavit. One of those times was just before he was stopped for the August traffic offense.
While they were combing through his cellphone history, investigators were also tracking his car as he drove home for the winter break. An automatic license plate reader in western Colorado picked up the Elantra on Dec. 13. Police in Indiana stopped the car Dec. 15.
The next day, surveillance video showed the Elantra at Kohberger’s family home in Albrightsville, Pennsylvania, according to the court documents.
Investigators hunt for DNA in trash
On Dec. 27, police collected garbage from outside the Kohberger home.
The evidence was sent to the Idaho State Lab for testing and a DNA profile was compared with DNA discovered on the knife sheath.
According to the affidavit, the DNA retrieved from the trash indicated a high probability it is from the biological father of the person who left DNA on the knife sheath at the crime scene in Moscow.
Investigators did not specify what type of DNA was tested. Experts, however, say the evidence made public Tuesday is likely to be only a small sample of what led them to believe Kohberger is the perpetrator.
Todd Martin, a retired lieutenant in the Texas Rangers, for whom he investigated all kinds of violent crimes, said police never want to reveal more than they have to in their arrest affidavits because they want to maintain a strategic advantage over the accused.
The Moscow Police Department’s affidavit did just that by connecting enough dots to show probable cause that Kohberger committed the murders, said Martin, who isn't connected to the investigation.
There's likely to be a lot more evidence — more sightings of the Elantra, more information about where Kohberger's phone traveled — that was not included, Martin said.
Howard Ryan, a retired investigator for the New Jersey State Police and a forensics consultant for law enforcement, said: "This is to get him in pocket and not show their whole hand. They gave about 10% — just enough for an arrest."