A 23-year-old woman was inappropriately touched after she fell asleep on a train travelling between London Paddington and Reading.
The incident happened between 1.30am-2.30am on July 24 as the woman was travelling to Reading after a night out in London.
British Transport Police (BTP) have released CCTV images of a man they would like to speak to as officers believe he will have information which can assist the investigation.
He got off the train at Reading Station.
Detective Constable Steve Eyers said: “A man boarded the train at London Paddington and sat opposite the woman. During the journey, the woman fell asleep and awoke to find the man touching her.
“Any form of unwanted sexual behaviour is extremely disturbing and we are committed to tackling these offences in whatever from they take.
“Thankfully crimes of this nature are rare on the railway but, when they do happen, they are all the more frightening because of the relatively confined space."
Call BTP on 0800 405040 with information and quote incident reference GSUB/B5 of 27/08/14.
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