Investigators were able to identify the suspect in the killings of four University of Idaho students through a combination of DNA evidence, cell phone records, surveillance footage and a witness who said she saw him leaving the scene of the crime, according to newly released court documents.
According to an affidavit unsealed on Thursday, authorities identified Bryan Kohberger, a 28-year-old Ph.D. student and teaching assistant in the Department of Criminal Justice and Criminology at Washington State University, as the lone suspect in the Nov. 13 stabbing deaths of Kaylee Goncalves, 21, Madison Mogen, 21, Xana Kernodle, 20, and Ethan Chapin, 20, in an off-campus home in Moscow, Idaho, using a combination of cell data, surveillance video and genetic evidence left at the scene.
A surviving roommate told authorities that she heard crying, opened her door and saw a man in black clothes and a mask walking past her in the house on the night of the killings.
The roommate, identified in the affidavit as D.M., said she didn't recognize the man, who walked toward the back sliding glass door as she stood "frozen" and in "shock."
She described the intruder as 5-foot-10 or taller, and "not very muscular, but athletically built with bushy eyebrows." Law enforcement later determined that Kohberger matched the description the surviving witness provided.
Police also discovered a “tan leather knife sheath” laying next to Mogen’s bed, according to the affidavit.
The sheath was stamped with a U.S. Marine Corps insignia and was processed by the Idaho State Lab, which “located a single source of male DNA” left on its button snap.
On Dec. 27, FBI agents in Pennsylvania “recovered the trash from the Kohberger family residence” in Albrightsville, Pa., and sent it to the lab in Idaho, which matched the “DNA profile obtained from the trash and the DNA profile obtained from the sheath.”
Kohberger was arrested at his parents’ home in Pennsylvania on Dec. 30. He waived his extradition to Idaho, where he was arraigned on murder charges.
Investigators were able to identify Kohberger’s vehicle, a white Hyundai Elantra, from surveillance footage taken near the scene and track it to the WSU campus in Pullman, Wash., which is about a 15-minute drive from Moscow.
Police also used data from Kohberger’s cellphone data and license plate readers to track his movements before and after the killings.
Kohberger and his father drove from Idaho to Pennsylvania for the holidays, arriving in the commonwealth on Dec. 17. They were stopped twice by police in Indiana. According to multiple reports, the FBI requested Indiana police pull the car over so that investigators could get a clearer image of Kohberger’s hands.
Authorities have not publicly identified a motive for the killings.
According to the unsealed affidavit, data from Kohberger’s cellphone suggests he was in the area of the area victims’ residence on at least 12 occasions prior to the night of the killings.
The affidavit also states that a Reddit survey posted by Kohberger as an undergraduate student sought participants for a research project “to understand how emotions and psychological traits influence decision-making when committing a crime.”