An 18-year-old has been sentenced to five years in prison for shooting and killing a teenage girl who was running from a house party that was getting out of hand.

Angelo Alvarez was indicted on one count of first-degree murder with extreme indifference and five counts of attempted first-degree murder with extreme indifference last March for the Sept. 17, 2016 incident.

He pleaded guilty to second-degree murder in October. His five year sentence was conditional, Chief District Judge Patrick Murphy said, and if he fails to comply with the “strict requirements,” he will receive 20 years in prison.

In a news release, District Attorney Dave Young said “the punishment doesn’t fit the crime and no one is happy with this outcome, but we have to look at what justice is in this case, and in my mind, this is justice.”

Prosecutors say Alvarez fired multiple shots into a crowd of people outside of a high school homecoming party in Thornton.

Haley Vargaz, a Thornton High School junior, was shot in the back and killed.

She was trying to get to her car after the party got out of hand, fights erupted and multiple people fired guns into the air, according to prosecutors.

Young said Alvarez was offered the plea deal because “there was significant risk that the defendant could be found not guilty based on the evidence in this case.”

“This is as sad and tragic a case as I have seen,” Young said in a news release. “Angelo Alvarez fired a gun into a crowd of people at a party without any thought of the consequences and Haley Vargaz was killed. This remarkable young woman had won a battle with cancer but her determination in overcoming cancer could not save her from the defendant’s bullet. The loss of Haley has devastated her family and everyone who knew her.”