Police say an upstate 15-year- old boy is being held in a psychiatric hospital after he stockpiled gasoline, propane, fuses and a machete for a planned attack at an Orange County school on the anniversary of the Columbine HS killings.

The boy, whose name was withheld, was arrested Monday evening after police searched his home in Monroe, 45 miles northwest of New York City. Police say he told them he planned to attack Monroe-Woodbury HS on April 20.

Police say the boy recently transferred to another school and harbored grudges against former classmates.