After he was arrested in a school shooting rampage that left two classmates dead, Kip Kinkel lunged at an officer with a knife that he smuggled into the police station, authorities said Saturday.

Police said Kinkel, who is also charged in the shooting deaths of his parents, had a hunting knife taped to his leg that escaped notice when he was arrested following Thursday's morning's cafeteria shooting at Thurston High School.The freckle-faced 15-year-old was handcuffed and placed in an interview room at the police station while an officer left briefly to secure his weapon, said police spokeswoman Rosemary Pryor.

Kinkel maneuvered his handcuffed arms to his front and lunged at the returning officer, she said. "The officer stepped back and used pepper spray on Kinkel."

Police made the disclosure after finally clearing away the bodies from Kinkel's home, along with five "sophisticated" bombs - one of which exploded as demolitions teams were attempting to disrupt it. There were no injuries.

Also found in the home were 15 other inactive explosive devices and detailed bomb-making instructions that had been taken off the Internet. Police confiscated a computer from the home.

On a shelf in his bedroom there was a pineapple-style hand grenade confirmed as empty. Two empty howitzer canisters sat at the foot of his bed.

In a crawl space underneath the house, there was a 6-inch cube of a white chalky substance wired to batteries and a kitchen timer.

In his closet, there was a one-pound device made from three soda cans and set with a hobby fuse.

In the attic, there were fireworks that had been cut open to collect the explosive powder. Investigators also found vinyl pipe-constructed devices that had electronic circuits and fuses that needed only a filler to make them into pipe bombs. One was 3 feet long.

"I continue to be taken aback by the youthfulness of the offender," said Lane County Sheriff Jan Clements.

Demolition experts had already disposed of four bombs Friday and were removing the body of Faith M. Kinkel, 57, when a fifth bomb was found.

It wasn't until Friday night that the home was deemed safe enough to resume the investigation and remove the body of William P. Kinkel, 59.