Updated

An accounting professor with secretly taping students in his San Francisco apartment's bathroom.

Prosecutors say Mark Landis, who taught at San Francisco State University and University of San Francisco, frequently hosted students at his home. In November, a male student found a camera hidden in a tissue box on the toilet.

District Attorney George Gascon told KTVU-TV that investigators identified 15 people who were videotaped, so Landis is charged with 15 misdemeanor counts of invasion of privacy. Gascon said he believes there may be more victims out there.

Landis, who is released on $100,000 bond, is scheduled to be arraigned Tuesday. The station said attempts to contact him and his attorney were unsuccessful.

Landis resigned at San Francisco State last Friday. He taught at USF for two years.