The threat was spotted by another student around noon on Tuesday at the school, said Stamford Police Lt. Tom Barcello.
The student immediately reported the perceived threat to school resource officers, administrators, and security guards who, along with police, were able to determine quite quickly the 15-year-old student who made the threat, Barcello said.
The student was arrested and charged with felony threatening, he added.
"We have zero tolerance for threats of any kind," Barcello said. "And, we take all threats very seriously."
He added that the department needs the public, including students, to help be the department's eyes and ears because they can't be everyone at once.
"It goes to the saying, if you see something, say something," Barcello said.
He also cautioned teens and students that these threats are serious crimes no matter what type they are or where they are made, either online, verbal or written.
After the teen was arrested, Barcello said they took the case to a judge, who thought it was serious enough to have the teen sent to juvenile detention.
Click here to follow Daily Voice Stamford and receive free news updates.