A former San Francisco State University professor is accused of filming students while they used the bathroom at his home, according to the San Francisco District Attorney's Office.
Mark Landis, 38, was arrested Wednesday and faces 15 counts of invasion of privacy, a misdemeanor. He is currently out of custody after posting $100,000 bail and is scheduled to be arraigned on Tuesday.
The district attorney's office said Landis would invite students from San Francisco State University and University of San Francisco to his 17th Street apartment.
"Obviously they were shocked by this behavior," San Francisco District Attorney George Gascon said of the victims. "It was so unexpected and you feel such an invasion of your privacy."
Officials said there are 15 victims, both male and female and all former or current students from SFSU and USF. Gascon said investigators believe there may be more victims.
In November 2013, a student visiting Landis at his apartment noticed a flashing light in the bathroom when they reached for a tissue, officials said. The student looked inside the tissue box and found a camera.
The student took the camera's memory card home and discovered videos and pictures, officials said. The student then brought the memory card to police.
San Francisco State University spokesperson Adrianne Bee said Landis resigned from his post on July 18. He had been an employee of the university, where he taught as an associate professor in the College of Business, since August 2006.
Landis also taught classes at the University of San Francisco for two years.
NBC Bay Area's Jean Elle and Bay City News Service contributed to this report.