LOS ANGELES (REUTERS) - A woman was found hanged to death in a Southern California high school classroom when students arrived on Monday, authorities said, and local media reported that she was a teacher at the school.

Paramedics responding to 911 calls from El Dorado High School in Placentia tried to revive the woman using CPR and advanced life-support measures but she was pronounced dead at the scene, said Captain Steve Concialdi of Orange County Fire Authority.

Concialdi said the woman was not a student at El Dorado High School but could not confirm reports by local KABC-TV and other local media that she was a teacher there.

He said the woman was found hanging when students who had arrived for classes found the door locked and summoned a teacher to let them in.

A Placentia police spokesman could not immediately be reached for comment.