KATU: CORVALLIS, Ore. – A 17-year-old West Albany High School student will be charged with attempted aggravated murder after the Benton County District Attorney said he planned to attack his school with bombs. Grant Acord will be charged as an adult. Attempted aggravated murder is a Measure 11 crime. Acord was taken into custody on Thursday at his Albany home after police received a tip that the high school junior had built a device and targeted his school. Saturday, District Attorney John Haroldson said Acord’s attack plan was patterned after the shooting at Columbine High School in 1999. “The charge of attempted aggravated murder requires that we prove that a substantial step was taken toward the completion of the crime. In this case, we would be relying upon evidence of plan. Diagrams, checklists, a plan to use explosive devices and firearms to carry out a plan specifically modeled after the Columbine shootings,” Haroldson said. Haroldson would not say when Acord allegedly planned to carry out the attack because that’s part of the evidence in the case. He said police found a timeline that included a specific date for the alleged attack to take place. Charges will be formally filed Tuesday morning. Monday is Memorial Day. “This is a case of a planned assault on a target-rich environment. And that target-rich environment is the West Albany High School.” Officers found already-built devices and bomb-making materials under the floorboards of Acord’s bedroom at his mother’s house, said Haroldson. On Friday, the Oregon State Police’s explosive unit removed the materials and at least six devices. The bombs included pipe bombs, Molotov cocktails, napalm bombs and and explosives made from drain cleaner, Haroldson said. The school was swept twice as a precaution, but nothing suspicious was found, Haroldson said. School will resume as scheduled on Tuesday. “The Albany Police Department has placed a lot of attention on insuring that West Albany High School is safe and secure,” he said. “The same is true for the neighborhoods that have been involved in the searches in this case.” Acord will also face charges of manufacturing a destructive device and unlawful possession of a deadly weapon with intent to use against another person. He is tentatively scheduled to appear in court Tuesday at 3 p.m.