The Metropolitan Police has launched an investigation into allegations made by Chelsea of "inappropriate language" from referee Mark Clattenburg directed at two of their players.
The police investigation follows an announcement from the FA on Monday that it has launched its own probe into the events which are alleged to have taken place during Sunday's 3-2 home defeat to Manchester United at Stamford Bridge.
A police statement read: "An investigation has been launched into alleged comments made during a football match between Chelsea FC and Manchester United FC at Stamford Bridge on 28 October 2012.
"This follows on from a complaint received by the Metropolitan Police Service on 29 October. Officers from Hammersmith & Fulham borough are in liaison with Chelsea Football Club and the Football Association. "At this time, the MPS has not received any complaint from either Chelsea Football Club, or the Football Association."
Chelsea have not made any complaint to police at this stage, and Professional Footballers' Association chief executive Gordon Taylor said: "Involving police or waiting causes a massive festering of the issue, which has continued to cause problems and is not good for the image of the game.
"Football has got to be confident enough to deal with it. I have said that to the House of Commons, the FA Council. We need to grasp the nettle and show we are more than capable of dealing with it."
He added: "I'm quite concerned that when this happened with the John Terry and Anton Ferdinand incident, the process got elongated. This time, I want football to learn from it and deal with it as transparently as possible.
"In football, the penalties can be severe. In a court of law, the penalty for racial abuse would be a small amount in comparison to what the FA could fine."
Chelsea lodged a complaint with the match observer following the game over what they claim were racist and xenophobic comments made by Clattenburg towards midfielders John Obi Mikel and Juan Mata.
Chelsea's complaint is that Mikel was the victim of a racist comment, while Spain midfielder Mata was allegedly called a "Spanish t**t" by Clattenburg.
The 37-year-old official will strongly plead his innocence when the FA interviews him over the alleged incidents, ESPN has learned.
Clattenburg has vowed to co-operate fully with their inquiries and is understood to be determined to clear his name. He has been offered the backing of the referees' union, although he has been removed from the list of referees for this weekend's fixtures in light of the allegations made against him.
The FA is yet to interview Clattenburg but is expected to do so, possibly after requesting a written account from him about what took place. He has already filed what is known as an 'extraordinary incident report', which is understood to mainly deal with a meeting which is alleged to have taken place in the referees' room after the match.
Information from the Press Association was used in this report