A Probable Cause Affidavit charging 28-year-old suspect, Bryan Kohberger with the murders of four University of Idaho students, became available on Thursday. And it meticulously linked to murders with his DNA, and his car. 

The Washington State University Ph.D. student was arrested Friday at his parents' home in Albrightsville, Pennsylvania. And he is charged with four counts of first-degree murder and one count of felony burglary. 

He was extradited Wednesday to where the crimes were committed. And made his first appearance in Idaho Thursday in a Latah County Court. 

Probable Cause Affidavit new evidence

The Idaho University slayings caused widespread speculation and created national interest. Police held back a lot of information to keep the suspect off guard and witnesses safe. And most of all make a solid case.

The new evidence includes:

• The suspect left behind a tan leather knife sheath on the bed next to Madison Mogen's right side.  The sheath is described as a United States Marine Corps aka "Ka-Bar" knife. And it had an “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 probable cause filing says.

• One of the two roommates, who survived the attack in the early hours of November 13 saw the murderer. She described him as wearing a black mask.

 She heard some activity within the 3-bedroom house. She heard what she thought was Kaylee Goncalves playing with her dog. And later she heard whispering and crying that may have been Kernoodle and the suspect.

•  Police said that Kohberger applied for an internship with the Pullman police in the fall of 2022. And in his application, he said he wanted to help "rural law enforcement agencies with how to better collect and analyze technological data in public safety operations." 
• Police were able to track the suspect's car through public video on the night of the murder. And in the weeks before the students were killed.
• The suspect's phone and bank purchase records were also tracked, and relevant information was reconstructed for the court documents.

• “Kohberger also posted a Reddit survey which asked for participants to provide information to 'understand how emotions and psychological traits influence decision making when committing a crime,'" the affidavit said.