A man who followed a woman home and groped her in the hallway is sought by police.
The man began following the 28-year-old as she stepped off a Tube train at Arsenal station in the early hours of 13 May.
He managed to engage her in conversation before forcing his way into her home in Hackney.
Police have released CCTV footage of a man they hope to speak with after no arrests had been made.
Officers were called to Mountgrove Road at 0130BST to reports of a sex attack.
Police said the man began following his victim at about 0020BST as she left Arsenal Underground station.
Once inside her home, he pushed her to the floor and carried out his attack before fleeing the scene.
It is believed he headed along Gillespie Road and towards Arsenal Tube station.
The suspect, who spoke with an English accent, is described as aged between 25 and 35, about 5ft 11in tall, of medium build and with short brown hair.
Det Insp Beverly Hawes said: "The victim suffered a terrible attack on her own doorstep.
"We would like to reassure the community that incidents of this nature are rare, but understandably can cause great concern."