Authorities believe they prevented what could have been an "unimaginable tragedy" they said Thursday by stopping a teen's plan to bomb schools in southern Minnesota.

Police arrested a 17-year-old suspect Thursday after finding him at a storage garage that had bomb-making materials inside of it. He was charged in juvenile court with four counts of attempted first-degree murder, six counts of possessing explosive or incendiary devices and two counts of criminal damage to property. 

The teen planned to carry out the attack in the next few weeks if he wasn't arrested. Captain Kris Markeson believed he was acting alone and was disturbed at the amount of guns and weapons the teen was able to obtain.

Thanks to a tip of suspicious person at the storage facility, police were able to investigate before the teen could do any harm to Waseca High or Waseca Junior High, his intended targets.

"This case is a classic example of citizens doing the right thing in calling the police when things seem out of place. By doing the right thing, [an] unimaginable tragedy has been prevented," Markeson said. 

Police also found a disturbing notebook that the teen used to detail his plans. In the notebook, the teen wrote about Columbine, Virginia Tech and Sandy Hook. He also idolized the Columbine shooters.

When the teen was initially questioned, he was not willing to reveal much information, instead he asked the police to guess what he was planning to do. When they guessed that he was making bombs, he began to talk.

He allegedly told police that he was going to shoot his family. After doing that, he was going to start a fire in a field to distract authorities. While the authorities tended to the fire, he planned on going to the school and setting off bombs in the cafeteria. He also told police he was going to throw Molotov cocktails and shoot students.

"We have escaped what could have been a horrific experience," school Superintendent Thomas Lee said.

Providing police with the key to his gun safe, the teen also told police where additional weapons were in his bedroom. Police recovered seven guns, three working bombs, black clothing and a ski mask from the teen's room.

The teen is currently being held in a juvenile detention center. His next court date is May 12.

The New York Daily News identifies the teen as John David LaDue.