(CNN) Nichole Cevario's journal was not your typical high school diary.

Rather than writing about schoolwork or personal relationships, the 18-year-old allegedly detailed her plans for a Columbine-style mass shooting at her Maryland high school, according to law enforcement.

And officials are convinced those plans might have come to fruition if one of her parents hadn't told school officers about them, the Frederick County Sheriff's Office said on Monday.

Police searched her home and found a shotgun with ammunition as well as materials for making pipe bombs, including pipes, shrapnel, fireworks, magnesium tape, and fuse material, police said.

"There's no doubt in our minds that we averted disaster there," Sheriff Charles Jenkins told reporters. "I've never seen anything like this, to be honest with you."

Police removed Cevario from Catoctin High School without incident last Thursday, the sheriff's office said in a statement. No other individuals assisted in the planning, Jenkins said.

"There's no doubt in our minds that we averted disaster there," Sheriff Charles Jenkins told reporters. "I've never seen anything like this, to be honest with you."

Police removed Cevario from Catoctin High School without incident last Thursday, the sheriff's office said in a statement. No other individuals assisted in the planning, Jenkins said.

No weapons or explosive material ever made it to school grounds, he said.

Police said they could not be sure she would have had the "will" to carry out the attack, but said she planned to die on the date she identified in the journal.

"The fact that a young woman could have this in her mind, this way of thinking and planning out and carrying out an attack much like Columbine or Sandy Hook," Jenkins said. "It shocks the conscience to see that someone at that age could be thinking like that."