Norwich have confirmed that a fourth allegation of racism towards defender Sebastien Bassong is being investigated by police.
Details of a tweet sent to Bassong, 26, have been passed to Norfolk Police.
Separately, a man has been released on conditional bail after alleged racial abuse towards Bassong during the match.
Norfolk Police are also investigating two tweets sent to Bassong after the 1-1 draw at Everton in November.
South Wales Police are continuing to investigate after a 23-year-old Swansea man was questioned on suspicion of a racially aggravated public order offence on Saturday.
Norwich manager Chris Hughton said a racial gesture had been made towards defender Bassong after Norwich's fourth goal.
The Cameroon defender complained to referee Howard Webb, who passed it on to the fourth official, and a male fan was subsequently arrested.
Norwich released a statement that said: "Norwich City regret to confirm four separate cases involving actual or alleged racist abuse aimed at our defender Sebastien Bassong have been reported to police in the last two weeks.
"Sebastien Bassong is a fantastic athlete and professional who we are proud to have on board at Norwich City.
"It is deeply disappointing that his recent excellent performances for the club should be tarnished by these incidents.
"Norwich City wish to reiterate that we have a zero tolerance stance on racism and will pursue these and any other examples of discrimination aimed at any of our colleagues to the fullest extent of the law."
Former Newcastle centre-half Bassong joined Norwich from Tottenham for an undisclosed fee in August and has made 14 Premier League appearances for the Canaries this season.