British Transport Police have released a CCTV image after a woman was allegedly sexually assaulted on board a train in Lincolnshire.
The incident is believed to have happened between 1.30pm and 2pm on 29 January, between Gainsborough and Lincoln Central stations.
A man is reported to have sat opposite a woman, and then repeatedly touched her inappropriately while asking her to come to his house.
He left the train at Lincoln Central and walked into the city centre.
Officers believe the man pictured be of use to their investigation.
Anyone with information should text BTP on 61016 or call 0800 405040.