The teenager accused of planning to bomb his high school told investigators he had placed several pipe bombs around his family's home, but authorities have found no explosives, a prosecutor said Wednesday.

Ryan Schallenberger may have just been bragging, state prosecutor Jay Hodge said

"He may have tried to make something and didn't finish it," Hodge said. "The kid is either just making it up or disposed of them."

A search that included the use of a bomb-sniffing dog found nothing Saturday, when the boy was arrested after his parents discovered he had ordered ammonium nitrate on eBay.

Authorities have said Schallenberger could have assembled bombs within minutes with materials they found at the home. A journal found there contained bombing plans, including a hand-drawn map of Chesterfield High School, and hate-filled pages that lauded the Columbine killers in Colorado, police said.

Schallenberger, 18, faces several state and federal charges, including attempting to use a weapon of mass destruction, which carries a possible life sentence.

Authorities initially said the teen had ordered 10 pounds of ammonium nitrate, but Hodge said Wednesday the material actually weighed 20 pounds.

Ammonium nitrate is a common fertilizer that has been a main ingredient in bombs used in attacks across the world, including the deadly 1995 Oklahoma City bombing that destroyed a federal building.

Schallenberger, a top student at the school, purchased the ammonium nitrate from a seller in Kentucky, federal officials said. A spokeswoman for eBay has said the California-based company has been cooperating with authorities in their investigation.

After authorities were alerted by his parents, deputies searched Schallenberger's home and seized several items, including a laptop computer, which was being analyzed by the State Law Enforcement Division, Hodge said. They also found an audiotape he left to be played after his death.

Schallenberger's mother and stepfather, John and Laurie Sittley, have not commented publicly. Their phone number is unlisted and their home off a dirt road about 10 miles from the school has "No Trespassing" signs posted.

Federal public defender Michael Meetze, who represents Schallenberger, declined to comment Wednesday.

Schallenberger's attorney on the state charge, William Spencer, did not immediately return a call seeking comment Wednesday.

Chesterfield is a town of about 1,500 in the northeastern part of the state.