Police have arrested a fellow classmate, a 16-year-old boy, suspected in the attack.
It happened Friday morning at Jonathan Law High School in Milford.
Authorities have identified the victim as 16-year-old Maren Sanchez. A staff member discovered her with neck injuries in a stairwell. She was taken to the hospital and pronounced dead.
Authorities haven’t determined a motive, but the police chief says investigators are looking into rumors a boy was angry because Sanchez turned down an invitation to be his prom date.
The prom was scheduled for Friday, but it has been postponed.