Six Millwall football fans have been arrested and bailed after an offensive banner about Bolton's Marvin Sordell was unfurled during their game against Derby County on Saturday.
Sordell was racially abused by one of the club's fans last month. A 13-year-old boy was banned from Millwall's ground after that incident. On Saturday a banner abusing Sordell was displayed by fans.
The banner did not contain racist abuse but was swiftly removed by Millwall staff.
A Metropolitan Police spokesman said six men were arrested on suspicion of public order offences and have been bailed until early December.
The club has so far refused to comment on the issue, and assistant manager Joe Gallen - standing in for Lions manager Kenny Jackett, who missed the game with flu - also opted not to discuss the matter.
Sordell took to Twitter after the Millwall match last month to claim that he and team-mates Lee Chung-young, Darren Pratley and Benik Afobe were subjected to racist taunts.
That sparked an investigation led by both clubs and last week Millwall confirmed the boy in question admitted to abusing Sordell and subsequently issued a written apology which the player accepted.