Detectives are appealing for witnesses after a woman was raped in Acton.
Police were called at approximately 21:25hrs on Saturday, 28 September to Langford Close, W3.
The victim, a woman in her 20s, told police she had been approached from behind by a man who put his hand over her mouth to stop her screaming. The man then forced her to an alley where he carried out the assault.
A member of the public heard what was happening and called police, but the man ran off towards Uxbridge Road, prior to police arrival.
The suspect was described as skinny with a London accent.
A man was arrested close to the scene on suspicion of rape, but he has now been eliminated from the inquiry.
The woman is being supported by specially trained officers.
Prior to the attack, the woman had left Acton Town Station and walked along Avenue Road and then Langley Drive, at some point along this route police believe the suspect began to follow her.
Officers have conducted an extensive CCTV enquiry and are releasing the only images they can find that show the suspect.
Detectives would like to speak with anyone who was in the area at the time and who heard or saw anything suspicious.
Anyone with information is asked to contact detectives at the West Area Command Unit via 101 or contact police via Twitter @MetCC quoting reference Cad 7575/28Sep
To give information anonymously contact Crimestoppers on 0800 555 111 or online at crimestoppers-uk.org.