A 17-year-old Washington County high school student died Saturday after firing a blank-shooting prop pistol used for a play.

Authorities say the Desert Hills student died from head injuries. The pistol was found in the student's hands shortly before the play "Oklahoma!" was scheduled to begin.

St. George Police Captain Bruce Graham says there were no bullets in the gun, but the gas in it has the same energy that a bullet does.

The boy was the only person in the sound booth when the cast of "Oklahoma!" heard a loud noise at approximately 6:20 p.m., Graham said.

The boy was taken to Dixie Regional Medical Center, but died about 10 p.m. as hospital officials were preparing to airlift him to a Las Vegas hospital.

The boy's name has not been released.

"I'm uncertain of the condition or circumstances of this unfortunate situation," said Marshall Topham, assistant superintendent of secondary education for the Washington County School District. "We're shocked and saddened to learn of it."

The cast and crew was rehearsing for the play just before their performance when the incident happened. Chase Leary was inside the high school's theater when he heard the prop gun fire.

"All I heard was screaming, and someone saying call 911," Leary said.

He said most people inside the theater were crying.

"I'm pretty overwhelmed," said Randy Johnson, a stage hand for the play, who wasn't inside the school when the shooting happened. ""He is a pretty close friend of mine."

Graham said detectives are investigating the incident.

This is the second time police have been called to the school as a result of a prop gun.

Police responded to the school on Oct. 10 after students reported seeing a person enter the school with a gun. The person who entered the school was actually a drama member with a prop gun for the play.