A California teacher was found hanging in her classroom in an apparent suicide, an act that came as an utter shock to the students who knew her.

Students walked into their El Dorado High School classroom Monday morning to find the teacher, who is still unidentified, hanging, police told CBS Los Angeles. Firefighters rushed to the scene in Placentia and administered CPR but they were unable to revive her.

"When police and fire arrived, the teacher was in cardiac arrest," Placentia police Lieutenant Eric Pointe told the Orange County Register. "After several minutes, she was declared deceased at the scene."

The woman's identity is currently being withheld but she is reportedly a 31-year-old photography teacher at the school.

Before she was found, students tried entering the classroom at around 8:40 a.m. but found it locked, which Pointe said is "not normal for that hour of the day." The kids asked a teacher in a neighboring classroom to open the door.

A teacher and some students took the woman down and called 911, CBS LA reported.

"I was in the class next door when I saw her students run out of the room with pale faces," a sophomore only identified as Holly told the Orange County Register. "Then teachers were running, then firefighters."

Classes were dismissed after staff gathered the entire student body into the gymnasium to inform them of the incident.

Junior student Leo Amaya, who took the teacher's class as a freshman, said she always seemed happy and enjoyed teaching her photo class outside.

"If you take into account how everyone reacted by crying and being upset, you'll see how everyone was completely surprised that it was her," Amaya told the Orange County Register. "She gave no signs of being depressed or sad."

Grief counselors will be available at the school starting Tuesday when classes resume.