Investigators have ruled out any other suspects in the stabbing deaths of four University of Idaho students.

Bryan Christopher Kohberger is awaiting extradition to Idaho, where he faces four counts of first-degree murder in the slayings of four University of Idaho students. Authorities tracked Kohberger for four days before arresting him at his parent’s eastern Pennsylvania home early in the morning on December 30.

Kohberger was enrolled at Washington State University as a criminal justice PhD student. Kohberger is set to appear in a Pennsylvania court room on January 3. He is expected to waive extradition and be taken back to Idaho.

New details are beginning to emerge over how the police zeroed-in on the suspect. Genetic genealogy evidence is predicted to have pointed investigators toward Kohberger.