NORRISTOWN — A woman admitted she helped her troubled, bullied 14-year-old son build a cache of weapons by buying a rifle and gunpowder, but investigators still don't know if she was aware her son was planning a deadly school attack.

Michele Cossey, 46, pleaded guilty Tuesday in Montgomery County Court to one count of child endangerment. She admitted that she gave him access to a rifle with a laser scope and gunpowder, which investigators said he was using to build grenades.

Her son, Dillon, planned an assault last year on Plymouth Whitemarsh High School, which some former schoolmates attended. Cossey, bullied over his weight, had left public school in seventh grade and was being home-schooled. Over time, he fueled his revenge fantasies through violent Internet sites, his defense lawyer said after his juvenile court plea.

Authorities did not think the school attack was imminent, but the boy did amass an arsenal — knives, swords, BB guns, the rifle and partly assembled homemade grenades — in his bedroom at his Plymouth Township home.

Police learned of the planned attack when Cossey invited a friend to join him. The friend went to police last fall.

Dillon Cossey is in a juvenile treatment facility, where he could remain until his 21st birthday.

PITTSBURGH — A Pittsburgh-area youth minister, whose sawed off shotgun was used in the accidental shooting death of a teenage girl, has pleaded guilty to involuntary manslaughter.Twenty-two-year-old Keith Owens of Homestead also pleaded guilty Tuesday to child endangerment and a weapons violation.Prosecutors say a 14-year-old boy accidentally shot 15-year-old Chelsea McAllister at Owens' house in November. The teens went there after a church event.Prosecutors say Owens had shown the boy an unloaded shotgun. They say Owens later reloaded it and hid it from view, but the boy retrieved the gun.