MINNESOTA -- The teenager had a plan.
According to authorities in Waseca, Minnesota, he was going to kill his family, start a diversionary fire, set off bombs at an area school, kill the resource officer there and then shoot students.
Frighteningly, the 17-year-old, who CNN is not naming because of his age, had the resources to carry out such an attack.
But because of watchful eyes, he didn't have the chance and is now behind bars.
"This case is a classic example of citizens doing the right thing and calling the police when things seem out of place. By doing the right thing, unimaginable tragedy has been prevented," the Waseca Police Department said in a Thursday statement.
Police were tipped off to the case two days earlier. Someone called about a suspicious person at a storage facility. When officers arrived, they saw what looked like bomb-making materials in a locker -- a pressure cooker, pyrotechnic chemicals, steel ball bearings and gunpowder.
The teen went with officers to the police station for an interview.
There, police say, he told authorities of his plan to kill his mother, father and sister, start a fire in rural Waseca to distract first responders, go to the Waseca Junior and Senior High School, where he planned to set off various bombs during lunch, kill the school resource officer, set fires, and then open fire on students.
A journal recovered from his home detailed his plan and preparations, said police, who believe he meant to carry out the attack in the next week or two.
'Shocked at all the news'
"I am shocked at all the news in one day," said Ryan Lano, who taught the teen guitar lessons for four years.
The boy and his sister would come for lessons together. They stopped coming four months ago.
"He would almost always come in with his sister who played the drums. They played music together," he said. "They were very close."
'Dealing with a lot of grief'
The teen idolized and studied the shooters responsible for the 1999 massacre at Columbine High School in Colorado, according to a statement of probable cause. He allegedly told police he wanted to carry out his attack on April 20, the anniversary of Columbine, but that April 20 this year was Easter and school was not in session.
The teenager has been charged with four counts of attempted murder in the first degree, two counts of attempted criminal damage to property in the first degree and six counts possession of an explosive or incendiary device, according to police.
It was not immediately clear Thursday whether he had retained an attorney.
His mother spoke briefly to CNN by phone.
"I'd rather not (provide a statement) at this time. Our family is dealing with a lot of grief. I appreciate your concern," she said, before hanging up the phone.