BALTIMORE -- Disturbing new details have emerged about a foiled mass-shooting plot aimed at a Maryland high school, CBS Baltimore reports.

Police uncovered a shotgun with ammunition, fireworks, and an arsenal of other materials for making bombs at the teen’s home in Thurmont, Maryland.

They say 18-year-old Nichole Cevario, a Catoctin High student, intended on carrying out an attack at the high school. Police say Cevario had been planning the attack for months.

“There is no doubt in our minds that we averted a disaster up there,” said Charles Jenkins of the Frederick County Sheriff’s Office.

Police say Cevario’s father foiled his daughter’s deadly plot after he found her diary which listed details of the attack, including a date next week she planned on carrying it all out.

“It was also clear in her diary that she planned to die during this event,” Jenkins said.

Investigators say the teen had also recorded the school’s emergency procedures, and had specifically referenced the Sandy Hook and Columbine massacres.

School officials, like many in the community, have been left in disbelief.

“We had no indication whatsoever that there were any issues with this student,” said Michael Doerrer of Frederick County Public Schools.

“You would never think that it would be her to do something like this. I knew something was up with her but I would have never imagined that it was this bad,” one student said.

In an interview, the Frederick County sheriff said the diary tells a different story.

“You could read the frustration, the emotional issues. Talking about how she could conduct this shooting, the fact that she may be the first female active school shooter in the country,” Jenkins said.

Cevario was taken to the hospital for evaluation and remains hospitalized.

Police stress that no weapons ever made it on school grounds. The teen faces a number of charges which could result in lengthy prison sentences.

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