Police matched Bryan Kohberger’s DNA to a knife sheath found at the scene of a quadruple murder leading to his eventual arrest in Monroe County, according to an unsealed affidavit of probable cause.

Kohberger, accused in the November slayings of four University of Idaho students is back in Idaho, where he’s charged with four counts of first-degree murder and felony burglary.

Police said they recovered trash from Kohberger’s parents’ house in Albrightsville, and a lab later determined the DNA from the trash belonged to a male who could not be excluded from being the father of the suspect who left DNA on the knife sheath.

In the affidavit, police also allege that Kohberger walked right by another female living in the home after allegedly killing Madison Mogen, 21; Kaylee Goncalves, 21; Xana Kernodle, 20; and Ethan Chapin, 20, on Nov. 13.

The female, identified in the documents by only her initials, D.M., told police she was awakened at 4 a.m. by what sounded like Goncalves playing with her dog in one of the upstairs bedrooms. A short time later she heard who she thought was Goncalves say something to the effect of “there’s someone here.”

A review of records obtained from a forensic download of Kernodle’s phone showed it could have also been her as she was using the TikTok app at around 4:12 a.m.

The female said she looked out of her bedroom but did not see anything when she heard the comment about someone being in the house. She opened her door a second time when she heard what she thought was crying coming from Kernodle’s room.

According to the affidavit, she opened her door a third time when she heard crying and “saw a figure clad in black clothing and a mask that covered the person’s mouth and nose walking towards her.”

D.M. described the figure as 5’ 10” or taller, male, not very muscular, but athletically built with bushy eyebrows,” the affidavit continues.

The female told police she locked herself in her bedroom after seeing the man.

Phone records, according to the affidavit, put Kohberger near the crime scene at least a dozen times before Nov. 13.

The phone did not report to AT&T between 2:47 a.m. and 4:48 a.m. on the night of the murders as investigators said they believe Kohberger turned it off to conceal his location.

Police said they used surveillance cameras to match a white 2015 Hyundai Elantra seen on the Washington State University campus to the vehicle spotted around the crime scene on the night of the murders.

Kohberger was arrested at his parents’ home in eastern Pennsylvania last week and agreed to be extradited to Idaho.

Based on information provided on the Washington State website, Kohberger is currently a Ph.D student in criminology. According to records provided by a member of the interview panel for the Pullman Police Department, Kohberger’s past education included undergraduate degrees in psychology and cloud-based forensics. These records also showed Kohberger wrote an essay when he applied for an internship with the Pullman Police Department in the fall of 2022 stating that he had interest in assisting rural law enforcement agencies with how to better collect and analyze technological data in public safety operations.

Kohberger also posted a Reddit survey, which can be found by an open-source internet search, asking participants to provide information to understand how emotions and psychological traits influence decision making when committing a crime.