A man who attacked a woman working as a so-called idol reportedly located her home by using an image reflected in her eyes in a photo on social media.
Twenty-six-year-old Hibiki Sato was indicted on Tuesday for attacking the woman in her 20s.
Sato allegedly covered the woman's mouth from behind with a towel as she returned to her condominium in Tokyo on the night of September 1. He pulled her down, groped her, and injured her.
Sato said he was a big fan of the woman. He reportedly told investigators he got a clue to her address from the photo showing a train station reflected in her eyes.
Sato used Google's Street View service to find the station, waited for her there and followed her.
Sato also found out where the woman lived by using videos she'd posted on social media that showed how her curtains were positioned and how lights shined through her windows.
Shuichiro Hoshi, a professor at Tokyo Metropolitan University, is an expert on the risks of social media.
He says smartphone cameras have become so advanced that personal information can leak in totally unexpected ways.
He urges social media users to avoid posting photos that give away private information, or to make images less clear to avoid targeting by what he calls digital stalkers.