On Friday, authorities searched the homes of 17-year-old Grant Acord's mother and father. Investigators found six bombs, a checklist and handwritten plan of his attack, which was apparently inspired by the Columbine shootings.
Acord faces six counts of manufacturing and possessing a destructive device. The bombs investigators found included pipe bombs, Molotov cocktails, a Drano bomb, a napalm bomb and explosives made from drain cleaner, said Benton County District Attorney John Haroldson.
Authorities also searched the teen's apparent target, West Albany High School about 75 miles south of Portland, but no bombs were found there.
Acord is a junior. Haroldson said he's not aware that the youth had any major problems, such as a suspension, at school. The district attorney said it did not appear the teen was targeting a specific person or group of people. He said Acord will likely be arraigned Tuesday in Benton County Circuit Court in Corvallis.
The Associated Press and ABC News contributed to this report.