When in Rome, by Patricia Highsmith

Isabella had wrapped her face, her neck, and was beginning to relax in the spray of deliciously warm water over her body when suddenly -- there he was again! An ugly grinning face peered at her not a meter away from her own face, with one big fist gripping an iron bar, so he could raise himself to her level.

"Swine!" Isabella said between her teeth, ducking at the same time.
"Slut!" came his retort. "Ha,ha!'

This must have been the third intrusion by the same creep! Isabella, still stooped, got out of the shower and reached for the plastic bottle of yellow shampoo, shot some into a bowl which held a cake of soap (she removed the soap), let some hot water into the bowl and agitated the water until the suds rose, thick and sweet smelling. She set the bowl within easy reach on the rim of the tub and climbed back under the shower, breathing harder with her fury.

Just let him try it again! Defiantly erect, she soaped her facecloth, washed her thighs. The square recessed window was just to the left of her head, and there was a square of emptiness, stone-lined, between the blue-and-white tiled bathroom walls and the great iron bars, each as thick as her wrist, on the street side.

"Signora?" came the mocking voice again.

Isabella reached for the bowl, Now he had both hands on the bars. and his face was between them, unshaven, his black eyes intense, his loose mouth smiling. Isabella flung the suds, holding the bowl with fingers spread wide on its underside.

"Oof!" The head disappeared.