A woman was sexually assaulted in front of her sister and other passengers as she travelled on a London train on a Sunday afternoon.
Other passengers stepped in to save the woman following the sexual assault, which happened around 2.10pm on February 11.
Police on Thursday released images of a man they want to trace following the incident.
The victim was travelling with her sister from Leyton to Gants Hill in east London, when a man crouched beside her to talk to her, said police.
“He then sexually assaulted her before other passengers stepped in to separate him from the victim,” said a British Transport Police (BTP) spokesperson.
“He continued to stare at and attempt to get close to the victim before leaving the train at Gants Hill station.”
BTP published photos of a man they believe “may have information that could help their investigation”.
The incident comes after BTP Chief Constable Lucy D’Orsi urged rail passengers to “speak up about violence against women and girls”.Speaking to LBC radio station last month, she said: “Have you ever been one of those people that thought ‘this is a bit uncomfortable’ in a carriage - ‘I’ll get out and get on the next carriage further down’?
“I’m saying tell us about it. Don’t be that person who just moves their position. I think we can solve this if we work together.”
Anyone who recognises him or has further information is asked to contact BTP by texting 61016 or by calling 0800 40 50 40, quoting reference 410 of 11 February.