Brewer Police say the 17-year-old had made some alarming remarks and other students reported them to officials.
Police talked to the student Friday and discovered he was in possession of a knife.
He was removed from school grounds and charged with terrorizing.
Police are now thanking the students who came forward for helping to keep the school safe.
There was also a police presence today at Oceanside High School in Rockland after a 20-year-old man allegedly made a threat on social media.
Thomas Sawyer, 20, was arrested over the weekend and also charged with terrorizing in what has become a rash of school threats facing Maine schools in the wake of the Florida school shooting.