The housemate then locked herself in her room and went back to bed.
When the surviving housemates woke up the next morning they summoned other friends to the house and one of those friends called police believing the housemates to be unconscious.
It was only then they discovered the horrific crime scene.
Court documents revealed the DNA of Kohberger was found on the button of a knife sheath at the crime scene.
In the affidavit, police corporal Brett Payne said phone data also showed Kohberger visited the area near the home around a dozen times before the attack.
He said those apparent visits all occurred late in the evening or in the early hours.
At the time of the murders, Kohberger was working on a doctorate degree in criminal justice at Washington State University, about 10 miles (16km) from the University of Idaho campus, where the victims studied.