BOLTON (CBS) — Police have charged a 15-year-old girl who allegedly wrote she was “gonna pull a columbine . . . before I graduate” at her school.

A caller notified Bolton police Wednesday that they saw the threatening post on social media app “Whisper,” originating from Bolton. The threat was typed over a photo of a Columbine flower.

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Police said officials at “Whisper” gave them GPS information to help them find the home from where the post was made.

“You really have to take every threat, no matter how it is projected, whether it be over the Internet, social media, telephone…seriously,” police chief Vincent Alfano told WBZ-TV’s Katie Brace.

Whisper assisted police in their investigation and within six hours, they were able to track down the girl who allegedly made the threat.

The investigation led them to a Bolton home where they determined a 15-year-old female student at Nashoba Regional High School posted the threat. She and her parents were “extremely cooperative,” police said.

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A licensed handgun at the home registered to a parent was voluntarily turned over to police.

The 15-year-old is charged with threatened use of deadly weapons and threatening to commit a crime, and she faces disciplinary action at the school.

Students were uneasy after learning about the incident.

“It’s a little bit scary that somebody would consider doing that,” said student Ethan Hill.

“It’s not a funny joke, but I hope it was a joke,” said student Sydney Cortez. “I hope that wasn’t actually the real thing because then that would be very unsettling.”

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Police said they are continuing to investigate, but it doesn’t appear that anyone else was involved in the threat.