MOSCOW, Idaho — After weeks of unease over the murders of four University of Idaho students in a house near campus, the authorities this week released their most detailed account yet of the investigation that led them to arrest a criminology student from a nearby university.
The documents detail an array of evidence about the suspect, Bryan Kohberger, 28, a graduate student at Washington State University, who said through a lawyer that he looks forward to being exonerated. The records also provided jarring new details about the night the four students were murdered, while raising fresh questions about a mystifying case in which authorities have not explained a possible motive.
Here are 10 key revelations made public on Thursday.
A roommate saw a masked man.
Investigators had previously suggested that two roommates who were inside the house on the night of the crime and were not attacked had been sleeping. But the records show that one of them awoke around 4 a.m. after hearing noises, a man’s voice and crying. That was around the time the authorities believe the killings occurred.
That roommate, according to the records, eventually watched from her room as a man in black clothing with a mask on his face walked past her toward the home’s back door. She reported locking her own bedroom door at that point, but it’s unclear from the records what transpired afterward.
Authorities were not summoned to the scene for more than seven hours.
Investigators found a knife sheath at the scene.
On an upstairs bed where two victims — Madison Mogen and Kaylee Goncalves — were found dead, investigators said they found a tan leather knife sheath.
The police said they were able to get a DNA sample from a button snap on the sheath, and later found a connection between that sample and DNA collected from Mr. Kohberger’s parents’ home in Pennsylvania.
That may prove to be a key piece of evidence, as authorities seek to tie Mr. Kohberger to the scene of the crime.
What to Know About the Idaho College Murders
The suspect applied to work at a local police department.
Mr. Kohberger had long taken an interest in criminology and criminal law.
He studied in Pennsylvania in part under Katherine Ramsland, a forensic psychologist whose books include “The Mind of a Murderer” and “How to Catch a Killer.” He researched the psychology of criminals when they committed crimes.
At Washington State University, he was pursuing a Ph.D., engaging in a class on DNA evidence and forensics in the weeks before the killings, while continuing to grade papers in the weeks afterward.
Authorities also disclosed that Mr. Kohberger had applied in recent months for an internship at the police department in Pullman, Wash., less than 10 miles from the University of Idaho campus in Moscow. He wrote an essay as part of the application in which he described his interest in helping rural police departments collect and analyze data.
A car passed the victims’ house several times.
On the night of the killings, investigators said, a white automobile could be seen on surveillance footage repeatedly passing through the dead-end street where the victims lived.
The vehicle, which the police said was a Hyundai Elantra, started appearing around 3:29 a.m., passing by the area three times before returning for a fourth time at 4:04 a.m., around the time that the surviving roommate was awakened and that the police believe the killings occurred. The vehicle, the police said, could be seen speeding away from the area at 4:20 a.m.
Audio captured a dog barking.
At around 4:17 a.m., a security camera near the home of the victims picked up distorted audio of what sounded like a whimper and a loud thud, investigators said. They also said a dog could be heard barking numerous times.
After the killings were discovered, police officers arriving at the house found a dog in one of the rooms. The dog belonged to one of the victims, Kaylee Goncalves.
One of the victims may have been awake.
While the coroner has said that all four victims were probably asleep at the time of the killings, investigators suggested in the new court records that at least one of them may have been awake.
Xana Kernodle received a DoorDash delivery around 4 a.m., just before the arrival of the white vehicle, the investigators said. A forensic review of her phone also suggested that she was using the TikTok app at around 4:12 a.m.
A campus officer found Kohberger’s car.
With the surveillance video in hand, the police began scouring the region for white Hyundai Elantras, and a campus police officer at Washington State University found one in November registered to Mr. Kohberger.
Investigators said they reviewed images of Mr. Kohberger and found that his physical appearance matched the recollection of the roommate who saw a man in the house, including his height, build and bushy eyebrows.
Police initially said they were looking for a 2011-13 Elantra, but later determined that it could also be from a model year as late as 2016. Mr. Kohberger had a 2015 Elantra.
Kohberger’s phone disconnected during the killings.
By the end of December, investigators were able to get records of the location of Mr. Kohberger’s cellphone.
The records showed that he had visited the neighborhood of the crime scene 12 times before the night of the killings, according to the police affidavit. On the night of the killings, his phone was in Pullman at 2:47 a.m., but then disconnected from the cell network.
The phone reconnected to the network at 4:48 a.m., at a location miles to the south of the University of Idaho. The phone eventually traveled back to Pullman.
The police suggest that the suspect may have returned to the crime scene.
Several hours after the killings, at around 9:12 a.m., Mr. Kohberger’s phone was detected in Moscow, connecting to the cellular network near the scene of the murders and staying there for nine minutes, according to the police records.
The phone then returned to the area of his home in Pullman. At that point in the morning, no one had called 911, so the police had not yet gone to the crime scene.
A DNA sample was taken from trash in Pennsylvania.
In the days after obtaining Mr. Kohberger’s phone records, investigators were in Pennsylvania, where Mr. Kohberger had driven for the holidays with his father.
Agents there recovered trash from the home of Mr. Kohberger’s family and shipped it to Idaho. Investigators said they worked to match a DNA profile found in the trash to a DNA sample collected from the knife sheath found at the crime scene. The analysis, the police said, indicated that the elder Mr. Kohberger was the father of whoever left DNA on the knife sheath.