Video (02:16) : John LaDue, the teen accused of planning an unfulfilled school massacre in this southern Minnesota city, pleaded guilty to a felony charge of possessing an explosive device.

– After more than a year of legal debate over what to do with a Waseca teen accused of planning a massacre at his school, John LaDue pleaded guilty Friday to a single felony count of possessing an explosive device.

Under terms of a plea agreement, LaDue will serve five to 10 years’ probation, including an unspecified amount of time at a secured autism spectrum disorder facility before moving to a halfway house and then intensive supervision.

A judge will issue the final sentence in October.

LaDue, now 18, was polite and matter-of-fact as he sat in orange jail garb Friday and admitted in court to possessing an explosive device as a minor, referring to what his attorney later described as a small “cricket” explosive.

In exchange for his plea, prosecutors agreed to drop the five remaining similar counts against him.

The “cricket” explosive was one of several items authorities found when searching LaDue’s bedroom and storage locker in late April 2014.

Waseca County sheriff's deputies led 18-year-old John LaDue back to the Waseca County jail after his hearing on Friday afternoon.

Police were alerted to LaDue by a suspicious resident who called them after seeing the teen enter a storage locker. That night, LaDue told authorities of his plans to shoot his family, then go to school with pressure-cooker bombs, firearms and ammunition. Authorities said they confiscated chemicals, several guns, ammunition and a few completed explosives.

LaDue, 17 at the time, was initially charged as a juvenile with four counts of attempted murder, two counts of first-degree damage to property and six counts of possession of a bomb by someone under 18. But a judge dismissed the attempted murder and property-damage charges, noting that the state had failed to show that LaDue had made a substantial step toward committing the crimes.

A state Appeals Court panel affirmed that judge’s decision, saying, “we cannot invite speculation as to whether the acts would be carried out.” The panel noted that in some states, the act of making preparations can be used to charge someone with attempted crimes, but Minnesota law specifically requires more than that.

Last month, a different judge certified LaDue as an adult, finding that doing so would “serve public safety and meet the needs of the child for treatment and rehabilitation.”

In a statement Friday, prosecutors said they have “always taken seriously the actions and intentions of John LaDue and have done everything within our power to ensure the best outcome to protect the public.”

But with the more serious charges dismissed, the possibility of a long prison sentence was gone, too: “Unfortunately, Minnesota’s attempt law does not cover the actions and planning exhibited by John LaDue,” the statement said. “It is our belief that this plea offer is the best outcome possible, under the circumstances, to ensure public safety.”

Under the agreement, LaDue will not be allowed to access the Internet while on probation and will not be allowed contact with Waseca Public Schools property.

Planned a massacre

LaDue’s case shocked the southern Minnesota town of 9,300 that is 80 miles south of the Twin Cities.

In police interviews, LaDue calmly and precisely described plans to “dispose of” his father, mother and sister by shooting them, then set a fire in the countryside for a diversion and carry out a massacre at the junior and senior high schools in town, including targeting a school liaison officer. He told police he wanted as many victims as possible because he thought it would be “fun” and he would be following his idol, Columbine gunman Eric Harris.

His plan was thwarted when a woman called 911 after she saw him fumble with a lock at a storage facility and shut the door behind him. Police found bomb-making materials, and LaDue, over the next several hours, told them of his plans. He directed police to a journal that he kept in his bedroom that also detailed his plot.

Unanswered questions

Outside the Waseca County courthouse Friday, LaDue’s father, David, said it had been a long, frustrating process for the family. They steadfastly stood by the teen, believing he never would have carried out a massacre, and they voiced concerns that he hadn’t been getting appropriate mental health therapy while he was detained.

Friday’s plea didn’t bring relief, David LaDue said, because of unanswered questions, such as where his son would be placed and for how long. “I want what’s good for him and I hope, for other people, that they will accept or be OK with it,” he said.

LaDue’s attorney, Steve Bergeson, agreed it had been a long process. “Now we can focus on the important thing, which is getting John the intervention and the therapy that is necessary.”

The Rev. Chris Meirose, of Waseca’s First Congregational Church, who held a prayer service shortly after the case came to light, said Friday he believes local reaction will be all over the map. Some people won’t understand why LaDue won’t be put in prison for a long time, he said, while others will be satisfied that something is being done; still others will be hopeful that the agreement will allow LaDue to get the help that he needs.

David LaDue, father of John LaDue, speaks to reporters outside the Waseca County Courthouse after his son's plea hearing, Friday, Sept. 18, 2015, in Waseca, Minn.

But, he said, the plea likely will bring closure to some because it will finally take the case out of the news.

Initially scheduled as a pretrial hearing, Friday’s proceedings quickly became more significant, closing out a case that has haunted Waseca for more than a year.

As for LaDue, Bergeson said he thinks his client is relieved.

“I’m happy that he’s going to be able to move on and that we were able to reach a reasonable resolution with the prosecutor, finally,” Bergeson said.