The teenager who killed four people and wounded seven others in a shooting at Oxford High School in Michigan was sentenced to life in prison without the possibility of parole.

The sentence was handed down on Friday (December 8) after an emotional day in court in which victims and the family and friends of those who died provided impact statements to the court.

Riley Franz, who was injured in the shooting, said she will never be the same after the attack.

"I mourn the person I used to be because, although I survived, the original pieces of me didn't," she said.

"Now when I sit at a school, I feel anxious — checking for all my exits, highly in tune with all movements inside and outside the classroom, flinching at every sound from the walking upstairs to a pencil dropping, and counting down the minutes until I feel that I can breathe again," Franz said. "I cannot remember what it's like to feel safe and secure in any space that I occupy."

The survivors detailed the harrowing moments when the shooter opened fire at their school on November 30, 2021.

Keegan Gregory was trapped in the bathroom and watched helplessly as his friend Justin Shilling was shot and killed.

"We were stuck helpless and cornered with no defense. I was right there when he was shot and killed, yet I couldn't do anything about it," Gregory told the court.

"I felt then, and still feel now, the guilt of surviving," he said. "I know that if it wasn't Justin's life that was taken, it could've been mine, and I'm forever grateful."

Another survivor said that she will never recover from the psychological toll the shooting took on her.

"November 30, 2021, I was given my very own life sentence," the student said. "I was only 14. I'm now sentenced to a lifetime of PTSD. I've spent hundreds of hours in therapy offices."

She then addressed the gunman directly.

"I will never have an ounce of forgiveness for you," she told him. "You're just an insecure, weak, fragile, insecure boy who could not deal with his own problems."

The shooter also addressed the court and said:

"I am a really bad person. I have done terrible things that no one should ever do."