Police guard an entrance to Jonathan Law High School in Milford, Conn., on Friday. (Michelle McLoughlin /Reuters)

A high school student in Connecticut was killed Friday morning after an attack by another student that led to a lockdown, an evacuation and yet another nightmarish scene at a school.

The attack occurred at around 7:15 a.m. at Jonathan Law High School in Milford, Conn., according to Keith L. Mello, the chief of police in Milford.

“This is a difficult day for Milford,” Mello said during a news conference Friday morning.

A male student assaulted a female student in the school’s hallway, Mello said. School staff members saw part of the attack and found her with “life-threatening injuries,” he said. The female student was taken to nearby Bridgeport Hospital and pronounced dead at 7:43 a.m., he said.

The student who was killed has been identified as Maren Sanchez, 16, a junior at Jonathan Law High School, Elizabeth Feser, the superintendent of the Milford Public School system, said at the news conference.

“She was extremely involved in the school,” Feser said. “Very, very well-respected…just a wonderful young woman.”

Sanchez was attacked in a hallway by a 16-year-old male student, also a junior, according to Keith L. Mello, chief of police in Milford, Conn. That student, who is in police custody, has not been identified yet due to his age, Mello said.

The attack occurred just 12 hours before the school’s junior prom, which had been scheduled for Friday night. There are multiple reports that the attack stemmed from the male student asking Sanchez to prom and being turned down; Bello said that the police have heard these reports and are looking into that.

It is believed that the attack was a stabbing, as Bello said there were severe injuries to Sanchez’s neck, but police have not confirmed that it was a knife attack yet. Earlier this month, a student with two knives slashed and stabbed multiple people inside a Pennsylvania high school.

Mello added that the stabbing was an isolated incident, but said the school was evacuated after the lockdown because it is an active crime scene.

Jonathan Law High School is located about half an hour south of Newtown, Conn., the site of a grisly mass shooting in 2012.