A US teenager who intended to blow up his school will be charged with attempted aggravated murder after a clutch of bombs were found in his bedroom, a prosecutor says. Grant Acord, 17, planned to attack his school in Oregon in a plot "forged and inspired" by a 1999 mass shooting at a high school in Columbine, Colorado, said Benton County District Attorney John Haroldson. Acord will be charged as an adult and also faces six counts of manufacturing and possessing a destructive device after investigators found the six bombs in a secret compartment in his bedroom, Haroldson said. Acord was taken to a juvenile jail on Thursday night after police received a tip that the youth was making a bomb to blow up West Albany High School. Haroldson said Acord had written plans, a checklist and a specific timeline for the attack. The explosive devices investigators found included pipe bombs, Molotov cocktails, a drain-cleaner bomb and a napalm bomb, he said. Police found no bombs during a search of the high school. Haroldson declined to provide the specific date on which Acord allegedly planned to attack the school, but said it would be included in court paperwork. 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." The district attorney said it did not appear that the teenager was targeting a specific person or group of people. He said Acord will probably be arraigned tomorrow. "I can't say enough about how lucky we are there was an intervention," Haroldson said. "When I look at the evidence in the case, I shudder to think of what could have happened here."