FONTANA (CBSLA.com) — A Fontana middle school teacher was found dead in a classroom Monday morning.

Wayne Ruble Middle School administrators discovered the teacher around 7:50 a.m. after opening the classroom’s door for students.

Police said an initial investigation determined the teacher passed away while completing paperwork after school on Friday.

Officials said it appears the instructor died of natural causes.

The name of the teacher is being withheld until family members are notified.