A video posted to YouTube begins with scores of students onstage, some in headdresses and others holding what appear to be pompoms, swaying to the right and left before jumping up and down and dancing in place.
That's when the stage at an Anaheim high school collapsed Saturday night, injuring about two dozen students. Some suffered broken bones, and most of the other injuries were minor to moderate, officials said.
Still, questions remain about why the stage collapsed and whether anyone knew about a weight limit or other issues with the structure.
The incident occurred at Servite High School, where about 250 girls from Rosary High School were on the stage at the time, police said.
"Early investigations suggest the front of the stage gave out due to weight," said Lt. Tim Schmidt of the Anaheim Police Department.
The Anaheim Fire Department was working to determine the cause of the collapse.
In a joint statement issued by Rosary and Servite high schools Sunday, officials said "a portion of the stage collapsed" during Rosary High School's production of "Red and Gold," its annual musical theater challenge.
Rosary is an all-girls school in Fullerton, Servite an all-boys Catholic school in Anaheim.
"Injured students were transported to local hospitals," the statement continued. "Our thoughts and prayers are with the students and their families."
Schmidt told the Orange County Register that by Sunday afternoon, all of the students had been released from the hospital.
He said the auditorium was built in the 1980s but an extension, the part that collapsed, was built in 1996.