Tyler Hilinski's death officially ruled suicide by Whitman County Coroner's office

— -- The Whitman County (Washington) Coroner's office has officially ruled Tyler Hilinski's death a suicide, it announced Thursday.

Hilinski, who was expected to be the starting quarterback at Washington State next season, was found dead Tuesday afternoon. He was 21. There was a rifle and a handwritten suicide note beside him, police said. The official cause of death, according to the coroner's office, was a self-inflicted gunshot wound to the head.

Pullman police are in the process of interviewing those close to Hilinski to try to determine a potential reason for his suicide, according to Pullman police chief Gary Jenkins. It's unclear, exactly, how long those interviews will take to complete, but Jenkins estimated they would be done by next week.

Police sent officers to Hilinski's apartment Tuesday afternoon, Jenkins said, at the request of a member of the WSU coaching staff. That staff member told police Hilinski had not shown up for a team workout and there was concern because it was out of character for him not to show up or call to say why he wouldn't be there.

"We are deeply saddened to hear the news of Tyler's passing," Washington State coach Mike Leach said in a statement Tuesday. "He was an incredible young man and everyone who had the privilege of knowing him was better for it. The entire WSU community mourns as thoughts and prayers go out to his family."

Hilinski, a Claremont, California, native, just finished his redshirt sophomore season for the Cougars. He started the team's bowl game against Michigan State and appeared in eight games, throwing for 1,176 yards and seven touchdowns. He enrolled at Washington State in January 2015 after attending Upland High School in Southern California.