The Metropolitan Police have launched an investigation into alleged comments made by referee Mark Clattenburg during Chelsea's contentious Premier League match against Man Utd.
It follows a move by the Society Of Black Lawyers which has asked the Met to look into whether there was a racially aggravated offence committed at Stamford Bridge on Sunday.
The Met will have to decide if there is a criminal case to answer.
Meanwhile, the FA will continue with its own investigation unless they receive a request to stop from either the police or the CPS.
Clattenburg aggrieved Chelsea by sending off two of their players and allowing an offside United goal in Chelsea's 3-2 defeat at Stamford Bridge.
Players Union Chief Gordon Taylor has confirmed one of the complaints is about racist language.
Mr Clattenburg, 37, has said he will co-operate with any investigation.
The Professional Game Match Officials body, which manages officials in the Premier League, has said Mr Clattenburg will not officiate a match this weekend.
"With any football match, the focus should not be on the officials but on the players and the game itself," the organisation said.
The referees' union Prospect has said it is "offering full support" to Mr Clattenburg.
"Prospect is committed to helping to eradicate racism in football and in society generally," said national secretary Alan Leighton.
"In the context of that commitment, Prospect is offering full support to Mark Clattenburg in relation to the allegations made against him. It is now important that the allegations are fully investigated through the proper process as quickly as possible."
Chelsea have already launched their own inquiry, after reports that the steward fell as home fans threw objects onto the pitch in the aftermath of Javier Hernandez's winning goal for United.
