We'll move on to the latest on the teen the police say was plotting a columbine-inspired attack on his high school in oregon. He'll be arraigned in court as his classmates head back to school. Abc's... See More
We'll move on to the latest on the teen the police say was plotting a columbine-inspired attack on his high school in oregon. He'll be arraigned in court as his classmates head back to school. Abc's neal karlinsky has the latest from albany, oregon. Good morning, neal. Reporter: Imagine coming back to school this morning to these two announcements, the school has been swept for bombs twice and is all clear and added security will be on hand just in case. That is the unfortunate reality after a student here was arrested for allegedly plotting a massacre. Police say 11th grade student grant acord was aplanning a killing spree in between doing his homework. Stockpiling a small arsenal in a secret compartment under the floorboards of his bedroom. This weekend a police bomb squad methodically deconstructed it pulling out pipe bombs, bombs made from drain cleaner, homemade napalm and molotov cockta cocktails. The plan unraveled when someone tipped off investiga by calling 911. This morning, the 17-year-old's classmates say they heard him talking about bombs but didn't think much of it. He just walked up out of nowhere and asked if we were talking about bombs and we all just kind of gave him a funny look and kept going on about the different materials you need to make a pipe bomb. Reporter: Investigators don't have a motive but say he was making a detailed plan complete with a time line and check list and a goal of pulling off something similar to the 1999 columbine high school massacre. Investigators say he even asked his friends to take a video of it. Our number one priority for our department as well as the school district is the safety of our students and staff. Reporter: Acord was known to be quiet, even aloof. A student who's known him since the third grade said he'd changed in recent years and wasn't the light-hearted kid she used to know. It's hard to believe someone you used to call your friend would want to do this to anyone. Reporter: Overnight acord's mother released a statement that offers some clue that reads "my heart goes out toryone with grant's struggle with a rare form of obsessive campus sink disorder. I grieve for my son but understand and support the efforts of law enforcement to keep the community safe."
This transcript has been automatically generated and may not be 100% accurate.