Liverpool's trouble-prone striker Luis Suarez sparked fresh controversy on Sunday when he appeared to bite Chelsea defender Branislav Ivanovic during their Premier League encounter at Anfield.
The incident occurred mid-way through the second half, with Liverpool trailing 2-1, and saw the Uruguayan apparently sink his teeth into the Serbian defender's upper arm after a penalty-area tussle.
Ivanovic pushed Suarez away but referee Kevin Friend did not appear to see the incident and took no action.
Suarez had earlier been booked for a handball that gifted Chelsea the penalty from which Eden Hazard put them 2-1 up.
Suarez, 26, has regularly hit the headlines since joining Liverpool from Dutch club Ajax two years ago.
He has frequently attracted criticism for diving and was banned for eight matches after being found guilty of racially abusing Manchester United's Patrice Evra during a game in October 2011.
In an apparent precursor to Sunday's incident, he was once banned for seven games for biting PSV Eindhoven player Otman Bakkal while playing for Ajax during a Dutch league game in November 2010.
He left Ajax for Liverpool before he could complete his suspension.