The Associated Press

SAN MATEO, Calif. (AP) - A 17-year-old boy accused of detonating two pipe bombs at a Northern California high school while armed with a chain saw, sword and explosives was charged Wednesday with attempting to murder two faculty members.

Alex Youshock, a former student at Hillsdale High School in San Mateo, also was charged with six other counts, including exploding or attempting to explode bombs in a school to terrorize others and possession of dangerous weapons - the sword and chain saw. Prosecutors said they would try him as adult for Monday's attack.

"He planned this elaborately," said Deputy District Attorney Karen Guidotti.

The prosecutor declined to discuss why Youshock allegedly wanted to kill teacher's aide Jana Torres and chemistry teacher Meghan Spalding. "We believe he had intent to harm them," she said.

Guidotti said Youshock was being prosecuted as an adult because of the serious nature of the alleged crimes and because he was about eight months from his 18th birthday. He was due to appear in court later in the day.

No one was injured in the attack, which quickly ended when faculty members wrestled the attacker to the ground.

Police Chief Susan Manheimer says investigators believe Youshock had planned to kill carry out a "cold-blooded plot of execution" on students and teachers because he was angry with the school administration.