The Metropolitan Police have confirmed they have launched an investigation into the alleged comments made by Mark Clattenburg.
The referee is alleged to have used inappropriate language to two Chelsea players during the 3-2 defeat to Manchester United at Stamford Bridge on Sunday.
Clattenburg is adamant he did nothing wrong and has already said he will co-operate with an FA probe in a bid to clear his name with the full support of the other match officials.
But he now faces a separate investigation after the Metropolitan Police confirmed they have received an official complaint from the Society of Black Lawyers and will be working alongside Chelsea to determine if any action needs to be taken.
One of the incidents is thought to involve Jon Obi Mikel, although early reports that the language used contained a racial element have not been confirmed by the London club.
Mikel angrily accused Clattenburg of abusing him in the aftermath of the game with Chelsea manager Roberto Di Matteo, assistant manager Eddie Newton and chief executive Ron Gourlay all present.
But Clattenburg's assistants on the day, Michael McDonough, Simon Long and Michael Jones, have denied hearing anything of that nature over the officials' microphone link-up.
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