PLACENTIA, Calif. -- A teacher was found hanging Monday inside a classroom in Placentia, California, CBS Los Angeles reports.

The unidentified female teacher was found deceased inside a classroom at El Dorado High School at 1641 Valencia Avenue just before school started Monday morning, according to Placentia Police Lt. Eric Point.

Students and another teacher got her down to the floor and called 911 about 8:40 a.m., according to Orange County Fire Authority Capt. Steve Concialdi.

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The discovery was made after students said the classroom door was locked during first period, according to Point. A neighboring teacher unlocked the door and students found the teacher hanging, Point said.

Police and Orange County Fire Authority paramedics responded and found a female adult in full cardiac arrest, Point said. After attempts to revive her were unsuccessful, she was declared dead on the scene, according to Point.

The death is believed to be a suicide, but no note was found at the scene, police said.

Officials gathered the entire student body into the campus gymnasium about 11 a.m. and informed them of the death, and then dismissed students for the remainder of the day, a school administrator said.

The teacher's age and name were not immediately released.

Crisis counselors will be on campus all week to support staff and students, district officials said.