Police are seeking 12 men in connection with mass violence at a football match during which a fan was slashed in the face.
Supporters clashed in Southwark, south London, before Millwall took on Everton in the FA Cup fourth round on January 26.
A 27-year-old man has been arrested on suspicion of wounding with intent, attempted grievous bodily harm and violent disorder and bailed until February 28.
The injured Everton supporter has posted a picture on social media showing a long scar down the right side of his face.