The Connecticut chief medical examiner says the 16-year-old girl fatally stabbed in a hallway of her high school died of wounds to her torso and neck.
The medical examiner's office said Sunday that Maren Sanchez's death was a homicide.
A 16-year-old classmate is charged with murder as a juvenile in Friday's stabbing at Jonathan Law High School in Milford.
Police didn't release the suspect's name, but people who saw him taken into custody identified him as a friend of Sanchez's.
Police are investigating whether Sanchez was killed because she turned down an invitation to be his date to prom.
The suspect's attorney says he is being held in a hospital under psychiatric evaluation. His arraignment is scheduled for Monday, but his lawyer says the boy won't attend.