Three Everton fans have been arrested in connection with a brawl between Millwall and Everton fans in which a man was slashed across the face.
Mass violence erupted at the FA Cup tie in London on 26 January. A man was left with a "life-changing" scar.
Two men, aged 19 and 49, have been held in Warrington and a third, 35, in Liverpool, the Met Police said.
All three were arrested on suspicion of violent disorder and bailed. A man arrested in February remains on bail.
Scotland Yard described it at the time as "some of the most shocking football violence seen for some time".
The injured man suffered injuries to his face in the brawl, not far from The Den - Millwall's home ground.
The force is continuing to appeal for information on images of nine Everton supporters they want to speak to in connection with the disorder.
Det Sgt Matt Simpson said the Met was working with Merseyside Police to identify them.
"We had an excellent response from the public when we issued the first set of images in relation to this incident, and I would now like to appeal again for the public's assistance in identifying these individuals, who we believe were involved in unacceptable disorder."