The trooper had stopped a pickup around 1 a.m. Thursday about 20 miles west of Seattle across Puget Sound, and radioed the location and license plate number, said Trooper Russ Winger. When the trooper didn't respond to status checks, a Kitsap County sheriff's deputy went to the scene and found the trooper outside his patrol car.
He was taken to St. Joseph Medical Center in Tacoma where he was declared dead.
Three hours later, officers found the truck abandoned on a county road near Port Orchard, about two miles from the shooting scene.
Troopers, deputies and other officers searched the area for the driver using dogs and questioning people. They urged residents to stay inside and call 911 if they saw anything suspicious.
Dogs did not pick up a track, Winger said.
Investigators know who the truck is registered to, but don't know if that person is a suspect in the shooting, Winger said.
"It's obviously a high priority and drawing a lot of attention," said Sgt. Ken Dickinson. "We're looking for whoever is associated with that truck."
The slain trooper is a veteran who worked out of Bremerton.
"He worked in the Kitsap area for quite some time," Winger said. "He was a co-worker of mine."
No other information would be released until his family was notified, said Bob Calkins, patrol spokesman. Dozens of patrol cars with lights flashing escorted an aid car carrying the trooper's body about 6:30 a.m. Thursday from the hospital to the Pierce County medical examiner's office.
The last Washington State Patrol trooper killed on duty was James Saunders, 31, who was shot in 1999 during a traffic stop in Pasco. Nicolas S. Vasquez pleaded guilty to aggravated murder and was sentenced to life in prison without parole.