BTP officers are today releasing CCTV images after a report of racist chants being shouted on a train from Blackpool to Liverpool.
The incident happened after 10pm on Wednesday 24 July.
A man is reported to have begun chanting racist slurs and using offensive language after boarding the train at Wigan North Western Station.
Officers believe the person in the image may have information that could help their investigation.
Anyone who knows him is asked to contact BTP by texting 61016 or by calling 0800 40 50 40 and quoting reference number 154 of 25/07/19.