Police in London are "assessing" a complaint from a member of the public accusing Chelsea and England captain John Terry of racially abusing QPR defender Anton Ferdinand, it was confirmed on Tuesday.
Terry has strongly denied hurling a racist slur at Ferdinand during Sunday's stormy west London derby at Loftus Road.
"We can confirm that police have been notified of an incident on Sunday 23 October involving alleged racial abuse," a Metropolitan Police statement said.
"This is currently being assessed by officers from Hammersmith and Fulham."
The claims against Terry emerged after video footage circulated on the Internet appearing to show the England star using racist language.
Terry denied abusing Ferdinand, saying the footage had been miscontrued.
"I've seen that there's a lot of comments on the internet with regards to some video footage of me during the game," he said.
"I'm disappointed that people have leapt to the wrong conclusions about the context of what I was seen to be saying to Anton Ferdinand. I would never say such a thing, and I'm saddened that people would think so."
Ferdinand, the brother of Terry's England team-mate Rio, has so far maintained a silence over the incident. The defender is expected to meet QPR officials later on Tuesday to discuss the issue.
Meanwhile Chelsea manager Andre Villas-Boas stood firmly behind Terry on Tuesday.
"He has put out his statement and we fully back John," Villas-Boas told a news conference. "John is a player who (represents) this country to the highest level internationally.
"He said to me the incident was a big misunderstanding. That's why he put his statement out straight away.
"I find it strange when people don't trust the words of a representative from your country."