A man has been arrested on suspicion of racially abusing Birmingham City's Juninho Bacuna in Saturday's derby against West Bromwich Albion.
The 50-year-old from Dudley was detained and questioned by police and has had his season ticket suspended by West Brom.
The Baggies beat their Championship rivals 1-0 at The Hawthorns through Andi Weimann's 85th-minute winner.
West Brom said anyone found guilty of racism would receive a lifetime ban.
Albion had warned fans about their behaviour before the fixture following their FA Cup fourth round match against fierce rivals Wolverhampton Wanderers the week before, where the game had to be stopped as trouble erupted in the stands.