Cassie Hense, 17, killed, Jose Flores, injured, taken to hospital, after a single-car crash on Wolf Road & 70th Place in Indian Head Park.

Students returning to Shepard High School on Monday after spring break were stunned by the news that Cassie Hense, of Alsip, who graduated early after the fall semester, had died in a car crash that left another former student critically injured.

Hense, 17, who worked on the backstage crew of the school's show choir, was killed Sunday afternoon in a traffic accident in Indian Head Park, according to the Cook County medical examiner's office. Hense was pronounced dead about 5 p.m., following a crash near Wolf Road and 70th Place.

An autopsy Monday determined that Hense, of the 5500 block of West Calumet Sag Road, died of multiple injuries from the crash, the medical examiner's office said. Her death was ruled an accident.

Another former Shepard student, Jose Flores, also of Alsip, was in the car. Indian Head Park police on Monday confirmed the crash but did not provide details, including who was driving.

Shepard choir director Michael Fallon and Principal Josh Barron said Flores, who graduated in June, was critically injured in the crash. They said Flores and Hense had dated in the past, but Fallon and Barron were not sure if they were still dating.

Fallon said Hense worked behind the scenes for the choir while Flores sang and was a "super ensemble singer for us."

"She actually stopped in to say 'hi' a few weeks ago," Fallon said. "She was getting ready to take classes at Moraine (Valley Community College). She was a very sweet kid. ... She was a really good kid, willing to do whatever it took to help the group.

"She had a real good sense of humor and had a good attitude about being involved with the other kids," he said.

Barron called the accident "very unfortunate," adding that "our thoughts and prayers are for Cassie and her family and for Jose to make a speedy recovery."

"She was a very involved student, very popular, especially among the music kids," he said. "That's a close-knit group, and they are hurting right now. There's never an answer for things like this. It's shocking when you have a tragic loss like this."