WASECA, Minn. (USA TODAY) -- Prosecutors say police likely foiled a planned school massacre when they arrested a teenager after he revealed an elaborate plot to kill his family and bomb the junior and senior high school.
A juvenile petition says John David LaDue, 17, of Waseca, is charged with four counts of attempted first-degree murder, six counts of possessing explosive devices and and two counts of first-degree criminal damage to property. All the charges reportedly involve a plot to kill his parents, his sister, and then a school liaison officer and as many students as he could.
At a news conference Thursday, Waseca Police Capt. Kris Markeson told reporters that authorities believe LaDue was acting alone and would have succeeded if he had not been caught.
A visibly shaken Markeson said he was disturbed by the amount of guns and other material LaDue obtained.
"He intended to set off numerous bombs during the lunch hour and kill the school resource officers and set fires and shoot students and staff," Markeson said.
The investigation began March 24, when melting snow revealed a pair of devices on the Hartley Elementary School playground in Waseca. Police say one of the devices had detonated while the second had failed to ignite.
Four days later a third device was found inside of a stuffed toy. It was already detonated.
On Tuesday, just over a month after the discovery of the explosives, 911 was called by a person who saw LaDue going into a storage unit and the caller thought he looked suspicious going in and out with a backpack.
Waseca Police arrested LaDue after executing search warrants at a residence and at the storage facility in Waseca.
"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.
A juvenile complaint says LaDue was arrested in a locker at the storage facility, surrounded by materials to make explosives. When pressed by officers, LaDue allegedly told authorities he would talk to them at the police station.
Once there, detectives say LaDue detailed an elaborate plot that started with murdering his mother, father and sister with a .22 caliber firearm. LaDue then planned to go to a remote area outside Waseca to start fires that would pull first responders out of town. At that time, investigators say, LaDue planned to go to the middle and high school campus during lunch and set off pressure cooker bombs to kill students. When the school police liaison officer responded, LaDue planned to shoot him, and then open fire on more students.
LaDue allegedly told authorities that he was fascinated by the school shootings at Sandy Hook, Virginia Tech and Columbine, and idolized Columbine shooters Eric Harris and Dylan Klebold.
Police say LaDue told them the plot was written down in a notebook and kept in a locked guitar case in his room. LaDue also said he had an assault rifle, a number of handguns and 400 rounds of ammunition in a gun safe that was also in his room. Search warrants were issued, and police recovered seven firearms, ammunition, and three functional bombs from LaDue's home, along with black clothing and a ski mask.
A bomb squad searched the storage unit and found three additional completed explosive devices and materials to make many more. Members of the bomb squad told prosecutors they were shocked by the volume of bomb-making materials and components LaDue had.
Based on statements from LaDue and items found in his home and storage locker, authorities believe the massacre was to take place in the next week or two.
Police said LaDue planned to die in the attack.
Those who know LaDue, like his guitar teacher of four years, Ryan Lano, find the news of the teen's plot surprising.
"I taught him guitar, met him when he was 13 years old," Lano said from his studio in St. Peter where he taught LaDue his last lesson in December 2013.
Lano said LaDue was a model student who was a very talented musician, so Thursday's news was as unwelcome as it was unsettling.
"Only adjective I can come up with is I'm shocked at the information, this is new to me," Lano said.
School Superintendent Thomas Lee said the 11th-grader was known to school officials but they had no major issues with him. He said teachers tried to reach out to him, but he was shy.
"It's not like he was unknown to us, said Waseca Schools Superintendent Tom Lee. "He was known. People made lots of contact with him. We tried to do everything we possibly could do to build relationships with him as well. But sometimes even when you're trying to do everything possible it doesn't turn out the way you want it to."
Ladue is in juvenile custody in Red Wing.
He was transferred there from Rochester after he made, what authorities are calling, "homicidal statements." His next court date is May 12.
Repeated efforts to reach LaDue's family in Waseca were unsuccessful.
Contributing: The Associated Press