The man who allegedly raped the American woman in Banjara Hills was familiar with the topography of her house and must have kept a tab on her movements, the police believe.

The two-floor house has two staircases and the investigators suspect that the rapist went to the penthouse by the rear stairway.

The penthouse, rented by the woman, has a bedroom, a front room and a kitchen. The rear stairway is not visible to outsiders.

“Only who had access to the house would know about it,” an investigator felt.

The window of the bedroom had no grills. Moreover, the doors of the window can be pushed open from outside though bolted by the inmates. There were no signs of a forced entry into the house. Apparently, the intruder knew the window panes could be opened from outside too.

Not leaving anything to chance, police are verifying credentials of all youngsters living in and around the locality who matched descriptive particulars of the rapist provided by the victim.

Police learnt that a case of Prevention of Immoral Trafficking Act (PITA) was registered four months ago after learning that a brothel was operated in a building in the area.

All the arrested persons in that case are being grilled.