The trio went to a police station in West Mercia and were detained by Scotland Yard officers on Sunday morning. They remain in custody.
Ian Mytton, 41, of Gateley Close, Redditch, Worcestershire has already been charged with the manslaughter of Michael Dye.
He will appear at Redditch Magistrates' Court on Monday.
Mr Dye, 44, was found hurt on September 6 before Wales played England in a Euro 2012 qualifier.
He was taken to Northwick Park Hospital but later died. The caused of death was found to be blunt trauma to the back of the head.
Tributes were paid to avid Cardiff City fan Mr Dye, including by the club's chief executive Gethin Jenkins.