A Menifee, California, man is accused of using the GPS data embedded in Facebook and Instagram photos to break into people’s homes and steal their underwear.

For at least the past year, 44-year-old Arturo Galvan is accused of breaking into people’s homes and stealing the underwear of both men and women, and also stealing electronics like laptops and tablets. But how did this creepy criminal find his victims? According to investigators, it was through a surprisingly simple but ingenious strategy.

Police say he hung out in public areas and searched for social media posts where people “checked in” to their location. He then allegedly searched their photos for attached GPS data and mapped out the info. From there, he broke into people’s homes and went on his underwear-raiding spree—stealing from both genders, and, according to police, both clean and dirty clothes. Galvan was finally caught when someone reported him for prowling through a neighborhood and police found the stolen electronics—and underwear—at his home.

While this is an unusually in-depth invasion of privacy (and just about the creepiest story ever), every Facebook user can take a practical lesson from it: protect your information very, very carefully. It never hurts to double-check your privacy settings and ensure your important info isn’t publicly available.