VICTORVILLE (CBS) — A Mesa Linda Middle School teacher found dead in a classroom early Tuesday morning is believed to have died of natural causes.

Tamara Joyce Dawe, 40, was found just before 8 a.m. inside a classroom at the school, prompting a school lockdown as a “precautionary measure,” San Bernardino County Sheriff’s spokeswoman Jodi Miller said.

No students were present at the school when the teacher’s body was found, according to the Victorville Daily Press. The coroner recovered Dawe’s body during the lockdown to avoid children being exposed to the scene.

There were no signs of foul play.