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Watch “48 Hours: The Idaho Student Murders” — correspondent Peter Van Sant reports on Saturday, Jan. 7 at 10/9c on CBS and streaming on Paramount+.

One of two roommates who survived the brutal attack that left four students dead at the University of Idaho told investigators that she saw a masked man leaving her home after the victims were fatally stabbed, according to court documents released on Thursday. The affidavit written by Moscow, Idaho Police Cpl. Brett Payne details the police investigation that followed November’s murders, which rocked the northern Idaho college town where it happened and has since held the attention of people across the country.

The documents were made public on Thursday as Bryan Kohberger, the 28-year-old criminology student arrested in connection with the homicide case, was set to appear in an Idaho courtroom for the first time since he was taken into custody at his parents’ home in Pennsylvania on Dec. 30. The affidavit also said Kohberger’s DNA was found on a knife sheath at the crime scene,

Kohberger’s arrest came almost seven weeks after University of Idaho students and housemates Madison Mogen, Kaylee Goncalves and Xana Kernodle, as well as Ethan Chapin, their classmate and Kernodle’s boyfriend, were stabbed to death at the women’s rental house before dawn on Nov. 13. 

Mogen, Goncalves and Kernodle were found dead in two bedrooms located on the upper floors of the home, which is near the university’s campus in Moscow and where they lived with two additional roommates, both of whom were present during the murders, according to the affidavit. It notes that, based on various mobile phone records, a DoorDash delivery receipt and footage taken from a security camera next door, detectives believe the killings likely took place at some time between 4 and 4:25 a.m.

Bryan Christopher Kohberger (inset) was arrested in connection with the murders of four University of Idaho students found dead in a home in Moscow, Idaho, on Nov. 13, 2022.

Idaho Statesman/Tribune News Service via Getty Images; Inset: Monroe County Correctional Facility

The surviving roommates, Bethany Funke and Dylan Mortensen, who are respectively identified in the affidavit as B.F. and D.M., slept in bedrooms on the first and second floors of the rental home. Kernodle’s bedroom was located on the second floor, investigators said, while Goncalves and Mogen lived in two adjacent rooms on the third and uppermost floor. Goncalves and Mogen were both found in Goncalves’ bedroom, as was the dog that Goncalves shared with her ex-boyfriend, Jack DuCoeur.

Mortensen, who also slept on the second floor, later told police in an interview that she opened her door three times after waking up at around 4 a.m. to what she thought “sounded like Goncalves playing with her dog in one of the upstairs bedrooms, which were located on the third floor,” according to the affidavit.

“A short time later, D.M. said she heard who she thought was Goncalves say something to the effect of ‘there’s someone here,'” the affidavit says. However, investigators pointed out that it could have been Kernodle’s voice, since records from a forensic download of her cell phone “indicated she was likely awake and using the TikTok app at approximately 4:12 a.m.”

Mortensen told police that she “did not see anything” when she looked out of her bedroom for the first time after hearing the voice. When she opened her door a second time, after hearing what she believed was “crying coming from Kernodle’s room,” Mortensen said that she heard a man’s voice say “something to the effect of ‘it’s ok, I’m going to help you,'” according to the affidavit.

Mortensen said that she heard crying again later and opened her door for the third time, investigators said in the document. When she looked out, Mortensen told police that she “saw a figure clad in black clothing and a mask that covered the person’s mouth and nose walking towards her.” She described the person as a man, standing at either 5 feet 10 inches or taller, who was “not very muscular, but athletically built with bushy eyebrows.” 

The roommate told police that the man walked past her while she stood at her bedroom doorway “in a ‘frozen shock phase,'” and proceeded to exit the home through a sliding glass door at the back entrance. Mortensen told police that she locked herself inside of her room after seeing the masked individual.

“This leads investigators to believe that the murderer left the scene,” they wrote in the affidavit.

While processing the crime scene, detectives found a diamond-shaped footprint, potentially from a Vans sneaker, near Mortensen’s bedroom door. They said the discovery substantiated her interview comments regarding his path of travel as he moved through the home and out the back door.