WASECA, Minn. (AP) - A teenager accused of planning a massacre at a Waseca school has pleaded guilty to one count of possessing an explosive device.

John LaDue pleaded guilty Friday in Waseca County District Court.

As part of the plea agreement, five similar counts will be dismissed and LaDue will be sent to a secure treatment facility for autism spectrum disorder patients. He'll then go to a halfway house.

LaDue is now 18. He was 17 when authorities say he plotted to kill his fellow students at Waseca Junior-Senior High School.

He was initially charged in spring 2014 with attempted murder and attempted first-degree damage to property, but those counts were dismissed earlier.

LaDue is scheduled to be sentenced Oct. 19.