The Metropolitan Police has launched an investigation into alleged racist comments made by referee Mark Clattenburg towards Chelsea players during the club's 3-2 defeat against Manchester United on Sunday.
The Football Association had launched their own investigation into the issue but neither they nor the Blues themselves were responsible for informing the police.
The Metropolitan Police Service confirmed they had acted on what they described as a "complaint" made by Peter Herbert, chair of the Society of Black Lawyers.
"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," a statement read.
"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. We continue to work in partnership with Chelsea Football Club and the Football Association in order to consider any allegation that is made in relation to the reported events."
Clattenburg endured a tough afternoon at Stamford Bridge on Sunday as he controversially sent off Fernando Torres for diving before allowing an offside Javier Hernandez goal to stand.