A female student at a Connecticut high school died Friday after she was attacked and stabbed inside the school's stairwell, authorities said at a press conference.

Maren Sanchez, 16, was pronounced dead at Bridgeport Hospital despite attempts by teachers and emergency responders to save her life after the attack inside Jonathan Law High School, authorities said. A student at the school and local media reports indicate that Sanchez was attacked because she refused to go to the prom with the attacker later in the evening.

The suspect, also 16, whose name is being withheld because he's a minor, was subdued by teachers immediately after the attack and is in custody, authorities said. The victim and suspect appeared to be "friends" on Facebook.

The school in Milford was put on lockdown Friday morning and students were sent home after the 7:14 a.m. stabbing. A former faculty member from the school told FoxNews.com that the suspect was arrested.

Police said that the attack was an isolated incident and no other students were in danger. The school's prom, scheduled for Friday night, was postponed to an as-yet undetermined date, a school official said. 

Sanchez was an honor student and swim team manager who was heavily involved with community service, particularly causes like underage drinking and veterans' services, school officials said.

A junior at the school told FoxNews.com that a teacher who witnessed the attack said Sanchez was asked to the prom by the attacker inside a stairwell at the school. Sanchez, who has a boyfriend, said no to the date, and the suspect began to strangle her, the student said. He pushed her down a flight of stairs and stabbed her.

Two male teachers eventually took the suspect to the principal's office until police arrived. The student said she saw the suspect being handcuffed and he "looked angry."

Police would not immediately confirm a motive in the attack.