Raheem Sterling was targeted during the first half of a Premier League match between Manchester City and Chelsea.
Chelsea have banned a fan for life for using racially abusive language towards England star Raheem Sterling.
Five other supporters have been temporarily excluded from Stamford Bridge for between one and two years for using abuse language and threatening and aggressive behaviour in the incident last December.
The Manchester City forward was targeted during the first half of a Premier League match between the two sides.
Chelsea said they delayed reaching a decision in the cases in order to not prejudice the related police investigation.
The Crown Prosecution Service recently revealed it had opted not to launch any criminal prosecutions over the incident.
The club said it decided to ban the fan for life having looked at video evidence, conducted interviews with potential witnesses and after seeking the advice of lip-reading experts.
Chelsea said that they concluded the fan in question had used racially abusive words.
Explaining its decision to issue the supporter with a lifetime ban despite the CPS not launching criminal proceedings, the club said: “While the club respects the decision of the CPS, the question that it had to determine was not whether a criminal offence had been committed, but rather whether the individual acted in breach of the ticketing terms and conditions.
“In this regard, the club operates to the civil standard of proof, which is entirely different to the criminal standard.
“In reaching its decision, the club took into account the denial made by the individual as well as a range of other evidence, including video evidence and evidence from two lip-reading experts – both of whom advised that the individual had used words that are racially abusive.”
All of the supporters punished were offered the chance to appeal and, where applicable, those appeals have been heard.
The five fans banned temporarily will be allowed back subject to “undertakings about their future behaviour”.
Chelsea’s statement added: “In this case the behaviour of all six individuals crossed the line of what is acceptable.
“Furthermore, in the case of the supporter who was found by the club to have used racially abusive language, there is no place for this behaviour at Stamford Bridge and a permanent exclusion was the appropriate sanction.
“Given the particular circumstances of this case, the club did not consider that attendance at an education course in return for a reduced sanction would have been appropriate.
“Chelsea Football Club finds all forms of discriminatory behaviour abhorrent and we will continue to operate a zero tolerance approach to any incidents of racism.
“We are proud to be a diverse, inclusive club where people from all cultures, communities and identities feel welcome.”