An 18-year-old student planned to bomb her Maryland high school and shoot people as part of a meticulously planned attack, authorities said.

Nichole Cevario — an honors student who took college classes in criminal justice — had stockpiled a shotgun, ammunition, and bomb-making materials (including nails and firework) at her home in Thurmont, Maryland, according to Frederick County Sheriff Charles Jenkins.

She was caught after one of the teen's parents — her father, according to NBC News — notified Catoctin High School officials last Thursday of a potential threat of violence and Cevario was removed from the classroom and turned over to investigators. Cevario was later taken from the school to a hospital for an emergency evaluation and remains hospitalized, officials said.

"This attack was prevented by the parents, who stepped forward," Jenkins said at a news conference. There is no evidence that anyone else was involved, he added.

The items found in Cevario's home that police say she planned to use for an attack on her Maryland High School. Fredericks County Sheriff's Department AP

Cevario's journal "clearly spelled out" detailed plans for an attack she had been working on for some time, including a timeline of the attack with her expectations for each stage, officials said. She had set April 5 as the day of the attack, the sheriff said. She was acquiring the materials and compiling details about school emergency procedures associated with drills conducted by school staff and on the school resource deputy.

Cevario's diary showed "evidence of mental health issues, emotional issues," Jenkins said. There was no indication that bullying was an issue, but the diary showed "a lot of frustration in her personal life," Jenkins said.

Investigators don't believe anyone was working with Cevario and they think they've eliminated any threat to the school and community. While explosive materials were located during the investigation, they weren't combined in any form that created an explosive device.

Once she's released from the hospital, police intend to charge Cevario with possession of explosive material with intent to create a destructive device and possession of incendiary material with the intent to create a destructive device.

A man who answered the phone at Cevario's home and her attorney, Alan Winik, declined to comment.

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