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 shone through her windows.