Google contacted the National Center for Missing and Exploited Children after finding three pornographic images in a user's email, leading to his arrest.
The Houston police said Google detected three inappropriate images of a girl in an email sent by John Henry Skillern, who is a known sex offender. After being informed of the images by the National Center for Missing and Exploited Children, the police obtained a search warrant and arrested Skillern.
Skillern has been charged with possessing child pornography after more evidence was found on his devices.
"He was trying to get around getting caught, he was trying to keep it inside his email. I can't see that information, I can't see that photo, but Google can," Detective David Nettles told KHOU-TV.
"I can't see that information, I can't see that photo, but Google can," Nettles added.
David Drummond, the chief legal officer for Google, has said the company assists the Internet Watch Foundation with identifying child abuse images so the company can then remove them from its search engine.
"We have built technology that trawls other platforms for known images of child sex abuse. We can then quickly remove them and report their existence to the authorities," Drummond said.
Google hasn't revealed whether it searches for other illegal activity like pirated content or hate speech.