Mark Child, a Downey High School English teacher who previously taught at Griffiths Middle School, died unexpectedly Thursday night. An official cause of death was not revealed. Downey Unified School District officials said Child was undergoing training in Garden Grove when he began to experience "health issues." He was rushed to UCI Medical Center where he died.

Students said they were told he died of a heart attack.

"The Downey High School family is devastated by this incident," the DUSD said in a statement. "We have mobilized psychologists and counselors to Downey High School to support the administration, staff, and students.

"Prior to coming to Downey High School, Mr. Child was also a teacher at Griffiths Middle School and certainly has connections throughout the community. Our thoughts and prayers go out to his wife and family. He will be greatly missed."

On Twitter, current and former students remembered Child as "an amazing man and great teacher."

"Mr. Child was the model every teacher should follow," wrote a former student using the handle @willuplez.

"Mr. Child was there for me throughout my whole graduation speech revision," shared another former student, @kiimbuhlee. "I thank him every time I go back to Downey high. I'm so sad."