An image taken on a mobile phone shows a male dressed in a red designer jacket clutching what appears to be a Valentino bag and wearing Apple AirPods.
A spokesman said: “Detectives would like to speak to the man in the image who they believe may have information that could help their investigation.
Police are hunting a man who carried out a solo sex act while staring at a woman passenger on a London Underground train.
He sat opposite her and began masturbating on the Northern line Tube carriage at around 11.40pm on August 22 last year.
British Transport Police appealed to anyone who may have experienced similar incidents to come forward.
