PORTLAND, Ore. -- An Oregon teenager intended to blow up his school in a plot "forged and inspired by the model of the Columbine shootings" and he will be charged with attempted aggravated murder, a prosecutor said late Saturday.

Grant Acord, 17, will be charged as an adult and also faces six counts of manufacturing and possessing a destructive device after investigators found six explosive devices -- including pipe bombs, Molotov cocktails, a Drano bomb and a napalm bomb -- in a secret compartment in his bedroom, said Benton County District Attorney John Haroldson.

Acord was taken to a juvenile jail Thursday night after police received a tip that the youth was making a bomb to blow up West Albany High School, located about 75 miles south of Portland.

Haroldson said Acord had written plans, a checklist and a specific timeline for the attack.

Police found no bombs during two separate searches of the high school.

Haroldson declined to provide the specific date Acord allegedly planned to attack the school, but said it would be included in court paperwork to be filed after the Memorial Day weekend.

"That said there were also some indications that it could happen at any time, too," Haroldson said. "So you have - A -the methodical planning and then - B - I suppose he could get really excited about it and go early."

Acord is a junior. Haroldson said he's not aware that the youth had any major problems, such as a suspension, at school.

"In any case that you have a young person that in essence plans to take a video game approach to killing people at school, you have to take a close look at the mental health issues," he said. "And the process will certainly provide for that once he's represented by counsel."

Phone listings did not appear to be available for either of the boy's parents to reach them for comment Saturday.

The Associated Press was not able to determine who would represent the boy in court.

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.

"I can't say enough about how lucky we are that there was an intervention," the district attorney said. "When I look at the evidence in the case, I shudder to think of what could have happened here."