Chelsea have confirmed an investigation will take place after a supporter at last night's Capital One Cup tie was photographed making an apparent racist gesture.
An image of a man in the home supporters section of Stamford Bridge, making what appears to be a monkey gesture toward Manchester United and England striker Danny Welbeck, was published in some of today's newspapers and has been doing the rounds on Twitter.
A statement from the club read: "Chelsea Football Club can confirm we are investigating an incident involving a member of the crowd at last night's game against Manchester United.
"The club will be examining all available footage and asks anyone who can identify the individual to contact the club.
"Chelsea FC is committed to removing all forms of discrimination and if we have sufficient evidence we will take the strongest possible action, including supporting criminal prosecution."
The police have also said they will be investigating the matter.
A statement read: "Today, Thursday, November 1, police have received a complaint regarding alleged racist behaviour at Stamford Bridge last night, Wednesday, October 31.
"An investigation has been launched. There have been no arrests and enquiries continue."
It is just the latest racism issue to rock the European champions, coming days after the club accused referee Mark Clattenburg of using "inappropriate language" toward midfielder John Obi Mikel.
Meanwhile Chelsea captain John Terry is currently serving a four-match ban for racially abusing Anton Ferdinand.
If the supporter is found guilty of racism, he is likely to be banned from Stamford Bridge for life considering that was the punishment meted out earlier this year to another supporter who was found guilty of abusing former player Didier Drogba.