Raphael Schklowsky, a drama teacher at Herndon High School, faces 20 felony charges of possession of child pornography and one felony charge of unlawful filming. 

Detectives discovered more than 3,500 videos on multiple electronic devices, according to the Fairfax County Police Department. Schklowsky, 36, was originally charged with four misdemeanor counts of unlawful filming on April 8. 

He was charged with the additional offenses today when he attended a hearing at the Fairfax County Courthouse. He is now being held on no bond.

Schklowsky has been on leave since his April 8 arrest. He was initially charged in early April when a woman told police she found a hidden camera inside an air conditioning vent in a home where she was working. Detectives found evidence of unlawful filming and arrested Schklowsky.

Photo via FCPD