Detectives have issued CCTV images of four men they want to trace over a mass brawl between rival Sheffield Wednesday and Chesterfield FC football fans.
A fight involving around 20 men and women broke out in Leicester in August last year, when Owls and Spireites clashed on a train.
The supporters were all travelling back from away games, with Sheffield Wednesday having played Brighton and Chesterfield having played Leyton Orient when the disorder occurred.
Seven Chesterfield supporters, aged 20, 23, two 28, 44, 46 and 48, all from Chesterfield, were arrested on suspicion of violent disorder following the incident and have been released on police bail until April 15.
They were questioned after a fight broke out on the 8.56pm London St Pancras to Sheffield service as it pulled into Leicester railway station at around 10pm on Saturday, August 9.
But now detectives from British Transport Police, which is leading the police probe into the incident, have released four CCTV images of four men they understand to be Sheffield Wednesday fans and who they believe could hold vital information.
Detective Constable Simon Courtney, who is investigating the disorder, said: “Approximately 20 people, both men and women, became involved in an altercation as the train pulled into Leicester station.
“We believe the people involved may have been travelling back from the Brighton v Sheffield Wednesday game, along with another group travelling back from the Leyton Orient v Chesterfield match.
“A number of people received minor injuries as a result, and the service was delayed for more than 21 minutes.
“We launched an investigation and seven men from the Chesterfield area were arrested at the time and interviewed then subsequently bailed.
“After reviewing CCTV, undertaking interviews and speaking to witnesses, new information has come to light and we are now in a position to release CCTV images of four additional people who we would like to trace in connection with the incident. We believe all of them are Sheffield Wednesday supporters.
“If you recognise any of the men pictured please contact us.”
DC Courtney added: “The majority of football fans cause no problems at all. Many thousands of supporters use the transport network without issue, and abide by the law.
“However, every weekend, the travelling public, law-abiding supporters and rail staff are distressed by anti-social and intimidating behaviour from a minority determined to cause trouble.
“This season, British Transport Police, working with the rail industry, has already made efforts to identify the small number of disruptive individuals that give clubs, and football generally, a bad name and will continue to do so.
“Those that are considered too drunk will be refused access to train services.
“If they are anti-social, they will risk facing arrest and in addition, we will seek banning orders in all appropriate cases.”
Witnesses or anyone with information about the incident or the four men in the CCTV images should call British Transport Police on 0800 405040 or text 61016.
Information can also be passed to Crimestoppers, anonymously, on 0800 555 111.
In all calls quote log MSUB/B8 of 20/3/2015.