Two fans have been arrested over racially-aggravated public order offences at the Chelsea v West Ham United Premier League match at the weekend, London's Metropolitan Police said on Monday.
A spokeswoman said bail had been granted to the two men with their return dates set for late March. Two further arrests were made at the match for different offences, affray and criminal damage.
Earlier on Monday police said they were investigating missile throwing by West Ham supporters towards their former player Frank Lampard after the Chelsea midfielder scored in the 2-0 win on Sunday.
"We are investigating instances of coin-throwing at Chelsea versus West Ham. There have been no arrests. Inquiries continue," a spokesman added.
Lampard, who joined Chelsea from West Ham in 2001, headed in the game's opener after 19 minutes at StamfordBridge and the goal was greeted with abuse from the nearby away fans who threw coins and hot dogs.
The England international's strike was his 200th for the European champions as he closes in on the club record of 202 set by Bobby Tambling in the 1960s and 1970s.
Photograph: Scott Heavey/Getty Images