Police are searching for a man who masturbated while staring at another passenger on a London Bridge train.
Detectives have released an imagine of a man they believe has information which could help their investigation.
The offender boarded a Thameslink train from London Bridge to Cambridge on Thursday August 31.
Between 3.30pm and 4pm he exposed his genitals and masturbated while staring at another person.
He later left the train at Hitchin station.
British Transport Police (BTP) detectives have asked anyone who recognises the man pictured, or anyone who has any other information, to contact them.
You can text 61016 or call 0800 40 50 40, quoting reference 204 of 31/08/2023.
Alternatively you can call Crimestoppers anonymously on 0800 555 111.