Bristol Central High School opened without incident this morning after the arrest over the weekend of a student who'd made threats.
Police deployed two extra officers at the school in addition to the usual resource officer stationed there.
"No one was in any danger but the threat was taken seriously by the police department and a juvenile was arrested" on Sunday, police Lt. Jack Michaud reported.
Police are not releasing details of the threats, or where or when they were made. The student's identity is not being released. The student was charged with threatening and breach of peace.
Schools Superintendent Ellen Solek said police learned of the threat about 5 p.m. Sunday.
Schools throughout the state are on heightened alert after Friday's tragedy at Sandy Hook Elementary School in Newtown.