A CCTV image of a man police want to speak to about an alleged early morning train sex assault on a teenage girl.
A teenage girl is reported to have been touched inappropriately on the hands, stomach and hair by a man.
Two male passengers intervened after growing concerned for the girl.
The incident happened at 7.30am on Monday, December 2, between Pye Corner and Cardiff Central stations.
The same man is then reported to have grabbed a woman, aged in her 20s, by the waist at Cardiff Central station.
British Transport Police say they would like to speak to the man in the image.
They would also like to speak to the passengers who intervened on the train to gather their witness accounts.
Anyone who knows him can contact BTP by texting 61016 or by calling 0800 40 50 40.
In both cases, quote reference number 70 of 02/12/19.
Alternatively, witnesses can call Crimestoppers anonymously on 0800 555 111.
