King County sheriff's Sgt. John Urquhart said the 51-year-old Maple Valley man, whose name hadn't been released, had left his car on a street on the south edge of downtown Issaquah about 11:15 a.m., and started walking south with the two guns.
The sheriff's office spokesman said the man pointed the rifles at pedestrians as he walked a half mile to Clark Elementary School but didn't fire the weapons at them, The Seattle Times reported. Witnesses said they saw him try to break into an unoccupied car in the school parking lot and fire one shot there, then fire more shots while trying to get into the cab of a parked backhoe.
It wasn't clear whether he directed his shots at anyone to that point but when city police showed up, Urquhart said the man allegedly dropped to the ground and began shooting at the officers and apparently at random, the Times said.
Four Issaquah officers returned fire and the man died of multiple wounds at the scene.
No one else was injured in the incident.
A youth football game being played at a nearby high school was halted and about 150 people were directed to go under the bleachers and were "told to keep down an be quite," parent Cheryl Puterman said.
"Everyone was in a panic," she said. "Then we heard the gunshots. Everybody was crying, scared."
The group wasn't allowed to leave for about 3 hours.