A computer service technician has been accused of installing spyware on customers' Apple computers that allowed him to take photos of women as they undressed or showered.
The 20-year-old from Fullerton, California, worked for Rezitech, a company that serviced computers in people's homes, according to a police statement.
The man allegedly installed spyware that allowed him to activate the webcam on the laptop remotely.
He may also have run the spyware on Macs connected to a university network, police said.
Fullerton Police said that the case came to light last year after a resident "contacted police about suspicious messages that were appearing on his daughter's computer."
The messages, which had the appearance of system prompts, allegedly prompted users to fix their "internal sensor" by placing their laptops "near hot steam for several minutes to clean the sensor".
"In response to this message, many of the victims would take their laptops into the bathroom while taking a shower," Fullerton Sgt. Andrew Goodrich said.
Police allegedly found "hundreds of thousands of images" when they searched the accused's home.