A Japanese man arrested on suspicion of stalking a female pop idol used the reflections of her pupils in photos she shared on social media and Google Street View to find where she lived.

The man also apparently learned even more by studying videos she posted from inside her apartment, observing her curtains and how light came through her windows

Tokyo police declined comment on the specifics, but confirmed that 26-year-old Hibiki Sato was arrested Sept. 17 on suspicion of indecent behavior in connection with stalking and causing injuries to the 20-year-old woman.

The police official, who spoke on condition of anonymity, said the case was related to the reports about a stalker and pupil images.

Police described Sato as an “avid fan.”

Japanese media reported that details in the woman’s selfies were used to identify the train station she frequented. Even casual selfies may show surrounding buildings that will allow people to identify the location of the photos.

Police say he hurt her and committed indecent acts, such as groping her after accosting her from behind and knocking her down.

Cyberstalking has been a problem for years, with criminals and perpetrators of domestic violence using hacking, illicit secret activation of microphones and cameras and other methods to track their victims.

It’s unclear how prevalent the use of high-resolution photos to locate potential victims might be.