FULLERTON, California -- A U.S. computer repairman suspected of installing spyware on laptops that enabled him to snap and download photographs of women showering and undressing in their homes was arrested Wednesday at his home, police said.

Police began investigating when a Fullerton resident complained about suspicious messages appearing on his daughter's computer last year. Trevor Harwell installed software that took control of computer webcams on his clients' Mac laptops, Fullerton police Sgt. Andrew Goodrich said.

The software sent fake error messages telling users to "fix their internal sensor soon," and "try putting your laptop near hot steam for several minutes to clean the sensor," Goodrich said.

The error message prompted some victims to take their laptops into the bathroom with them when they showered, he said.

"Once he had access, he would take photographs of the users, usually women," Goodrich said. "Often, the female victims were undressed or changing clothes. Harwell then stored the photos on a remote server, and eventually downloaded them on his own computer."

Detectives seized hundreds of thousands of still images and videos from Harwell's computer and identified several victims, Goodrich said.

Investigators believe Harwell, a technician for Rezitech Inc., may have exploited computers connected to Biola University's internal network. Harwell, 20, is a former student at the La Mirada school, where many of the victims attended.

Orange County Superior Court records show that Harwell faces 12 felony counts of computer access and fraud, The Orange County Register reported. It wasn't known Wednesday evening if Harwell had obtained an attorney.