Officers are investigating after a family and train guard were racially abused on board a train to Bassetlaw.
The incident happened on board the 9.35pm Virgin Trains East Coast service from London Kings Cross to Retford on Friday 17 February.
A man and woman were had joined the service at London with their six year old daughter. As the train was preparing to depart, a group of four males joined and sat within the first class section.
During the journey, the group of men racially abused a member of rail staff and the family.
Today (Thursday, March 16) officers are releasing CCTV of four men they would like to speak with in connection to the incident.
Investigating officer PC Kenda Bradbury, said: “I’d like to hear from anyone who might recognise the men in the CCTV images as I believe they have essential information.
“Behaviour such as this is unacceptable and we will do everything in our power to ensure that offenders are brought before the courts.”
Anyone with information is asked to contact British Transport Police by sending a text to 61016 or by calling 0800 40 50 40 quoting reference 225 of 16/03/2017.
Alternatively, pass information anonymously to Crimestoppers on 0800 555 111.