SNOQUALMIE PASS -- The Washington State Patrol is investigating a one-vehicle crash that killed a 53-year-old Maple Valley man Saturday.

Troopers are unsure when or how Edward C. Traweek left the eastbound lane of Interstate 90 near the summit of Snoqualmie Pass and crashed his 2002 Chevrolet Blazer, according to a State Patrol news release.

Traweek, who was not wearing a seat belt, was thrown from the vehicle during the crash and found dead at the scene, the release said.