Story highlights John LaDue appeared to be into heavy metal, gory movies and guns

Authorities were tipped off by someone who saw a suspicious person at a storage facility

He allegedly kept a journal detailing his preparations for the attack

A teenage boy had a plan.

According to authorities in Waseca, Minnesota, John David LaDue, 17, 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.

CNN does not usually publish the names of minors charged with crimes but is naming him in this case because his name has been widely reported in his community.

Frighteningly, police say, LaDue had the resources to carry out such an attack.

But because of watchful eyes, he 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.

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Police were tipped off to the case two days earlier. Chelsie Shellhas called them about someone acting suspiciously at a storage facility.

"He shut the door, and I thought it looked funny," she told CNN affiliate WCCO . "Because, normally, we see people come here, and it doesn't take them 10 minutes to open a storage shed, so that's why I called it in."

When officers arrived, they saw what looked like bomb-making materials in a locker: a pressure cooker, pyrotechnic chemicals, steel ball bearings and gunpowder.

LaDue 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 and start a fire in rural Waseca to distract first responders. Then, they say, he said he wanted to go to 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.

Liked guns, heavy metal

If his Facebook page is any indicator, LaDue is partial to the dark side, and he "likes" assault rifles: the AK-101, Heckler & Koch SL8 and Steyr TMP.

In a photo, he can be seen picking an electric guitar with a skull on its shoulder strap; his preferred bands -- more than 190 of them in total -- are predominantly heavy metal.

His taste in movies is dominated by blood, gore, combat and fisticuffs. His favorite authors are Stephen King and the master of literary darkness, Edgar Allen Poe.

He also seems to like to hunt. His avatar is a picture of himself in hunter's orange, posing with a slain deer with a rifle draped over it.

"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 that he wanted to carry out his attack on April 20, the anniversary of the massacre, 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 of 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.