An affidavit in the case against the University of Idaho killings suspect says police connected Bryan Kohberger's DNA to the case by searching his parents' garbage bin

• Prosecutors released the probable cause affidavit in connection to the Idaho killings suspect.
• It details what led police to arrest Bryan Kohberger, who is accused of stabbing four people.

Authorities discovered DNA linked to the 28-year-old man accused of killing four University of Idaho students on a leather knife sheath in one of the victims' bedrooms at the crime scene and made a DNA match by searching his parents' trash bin, according to a newly released affidavit.

The document details the evidence that authorities used to get a warrant to arrest Bryan Kohberger, a Ph.D. student in the criminal justice program at nearby Washington State University.

Kohberger lived just miles from the Moscow, Idaho, rental home where victims Kaylee Goncalves, 21, Madison Mogen, 21, Xana Kernodle, 20, and Ethan Chapin, 20, were stabbed to death, likely while they slept, on November 13, officials have said.

According to the affidavit, which was written by Cpl. Brett Payne of the Moscow Police Department and released by prosecutors on Thursday, authorities discovered a tan leather knife sheath laying on the bed where the bodies of Mogen and Goncalves were found.

According to the document, the Idaho state lab located a single source DNA on the knife sheath, which had "Ka-Bar," "USMC," and the United States Marine Corps eagle globe and anchor insignia stamped on the outside of it.

"The Idaho State Lab later located a single source of male DNA (Suspect Profile) left on the button snap of the knife sheath." the affidavit said.

Late last month, before Kohberger was arrested in connection to the killings, authorities went through the trash from Kohberger's parents home in Albrightsville, Pennsylvania, and sent the evidence to the Idaho state lab for testing, the affidavit says.

A DNA profile from the trash and the DNA profile from the knife sheath found in the Moscow, Idaho, home "identified a male as not being excluded as the biological father of the Suspect Profile," according to the affidavit.

It added, "At least 99.9998% of the male population would be expected to be excluded from the possibility of being the suspect's biological father."

Police also linked the suspect to the killings through his car, a Hyundai Elantra, and cell phone records, according to the affidavit.

Authorities arrested Kohberger last week at his parents' home in Albrightsville, Pennsylvania, after he made a cross-country drive there with his father from Washington.

Kohberger was arrested in his hometown on four counts of first-degree murder and one count of felony burglary in connection to the killings of the four college friends.

He agreed to be extradited from Pennsylvania, and law enforcement took him by plane to Idaho on Wednesday to face the charges.

Kohberger made his first court appearance in Idaho's Latah County Courthouse in connection to the case shortly after the release of the affidavit.

Goncalves, Mogen, Kernodle, and Kernodle's boyfriend Chapin were slain at the home where the women lived in the early morning hours of November 13 following a night out, police have said.

The killings left the small college city of Moscow on edge for weeks as no arrest in the case was made.

Police have still not recovered the murder weapon.

An attorney who represented Kohberger at his extradition hearing in Pennsylvania previously said that Kohberger believes he will be "exonerated."