A parent thwarted their teenage daughter’s plans for a mass school shooting after alerting officials she posed a potential threat of violence.

Nichole Cevario, a student at Catocin High School in Maryland, had been planning the shooting for some time and had even set a date in April for her attack.

The 18-year-old’s diary included a detailed timeline of execution, including expectations at each stage of the event and her own death.

She’d also compiled a list of security measures employed by her school, including emergency procedures and the manner of staff drills.

(Frederick County Sheriff’s Office)

Police learned she’d been acquiring the materials needed to execute the plot as they searched her home. There, they recovered items including a shotgun with ammunition, bomb-making materials to include pipes with end caps, shrapnel, fireworks, magnesium tape, and fuse material.

It’s believed no one else knew of Cevario’s plans, which was concocted – and to be executed – by the teen alone with no assistance from another.

Detectives continued their in-depth investigation scouring through her diary, recovering evidence from her home and conducting extensive interviews with her family, friends and peers.

(Frederick County Sheriff’s Office)

Cevario’s parent approached Catocin High School to alert them of the potential threat their daughter posed. The school, in turn, contacted Frederick County Sheriff’s Office.

The teen, who was at school at the time, was removed from her classroom and led to investigators. Preliminary investigations found not only was Cevario a threat to her school but to herself as police say it was “clear (she) was struggling with mental health issues”.

Cevario was taken for an emergency evaluation at Frederick Memorial Hospital, though police are to serve her with two arrest warrants upon her release: one for possession of explosive material with intent to create a destructive device, and another for possession of incendiary material with the intent to create a destructive device.