PHILADELPHIA — A 15-year-old boy stole his father's guns to use in a deadly, suicidal attack on his suburban Philadelphia high school, but a friend he asked to hold the weapons instead threw them in a river, authorities said.

The plan was thwarted when the father reported the three weapons missing, prompting a police investigation that ultimately led to an attempted murder charge filed Tuesday against his son.

Authorities say the Pottstown High School freshman took a revolver, two semiautomatic pistols and ammunition from his father's basement gun locker in early November. He gave them to a friend, hoping the friend would bring them to school when directed, authorities said.

The attempted murder charge is warranted because the teen took "substantial steps" to carry out the crime, Ferman said.