Officers have been pursuing several lines of enquiry, including analysing CCTV footage from on the train and at several stations.
This was a very distressing incident for the young boy who was travelling on his own. Everyone has the right to use the rail network without the fear of crime and we are doing everything we can to catch the person responsible. I urgently want to speak to the man pictured as I think he could greatly help the investigation. If you recognise him, or have any other information, please get in touch.
Anyone with information is asked to contact British Transport Police** on 0800 40 50 40, or text 61016, quoting background B3 of 28/04/2014. Information can also be passed to the independent charity Crimestoppers on 0800 555 111.
More top news
A windy but mostly dry start with the best of the bright spells towards the south east. Becoming cloudy with heavy showers later
Very windy with heavy rain moving east tonight. Becoming drier but staying windy later. Then sunny spells and strong winds tomorrow
Heavy rain and strong winds this evening. The rain will clear tonight but staying windy, especially along the coast