From the reflection in her eyes he "just" identified a train station, from there he followed her to the building she lives in. From posted indoor videos - and p

From the reflection in her eyes he "just" identified a train station, from there he followed her to the building she lives in. From posted indoor videos - and probably his own outside photos - he tried to identify the windows of her apartment based on things like window curtains and the direction of the sunlight. The linked article does not say whether he succeeded, just that he admitted to trying this.