(CBS News) Grant Acord, the Oregon teenager accused of plotting to blow up his school, West Albany High School located 75 miles south of Portland, will be charged with attempted aggravated murder in a court appearance on Tuesday. Acord, 17, will be charged as an adult and faces six counts of manufacturing and possessing a destructive device after investigators found six bombs -- ranging from Molotov cocktails to drano bombs -- under the floorboards in his bedroom.
CBS News senior corespondent John Miller, a former assistant director at the FBI, says Acord modeled his attack on the 1999 Columbine attack but the plot was foiled when classmates tipped off the authorities.
Acord's plan was "certainly well in development" based on the extent of weaponry found in a secret compartment in his bedroom, Miller said Tuesday on "CBS This Morning."
"He's also got written plans, operational plans ... as well as floor plans of the school," Miller said. "We don't know what the motive was and in his written plans, that wasn't clear."
Miller reports that Acord is said to have made strange comments to classmates and friends, a common practice of would-be violent offenders, known as leakage. "The good side of this familiar phenomenon, as we see in 80 to 90 percent of these cases, he has been telling friends that he had been learning to make bombs ... wanting to blow stuff up ... [and] one of them did [come forward] and that's what led police to the search which also brought them to the bombs."
"The model that's developing," in the wake of increased school shootings and terror attacks, Miller said, "is people actually are coming forward" and adhering to the common law enforcement prompt, "If you see something, say something."